May I ask how old you are?
(You say there’s too much at stake, but you can’t be vulnerable in front of him or let him know you’ve been mulling this over, and you’ve apparently had a few platonic dates and a kiss. I have trouble understanding just how much there could be at stake, since, no offense, you don’t seem to have much with him to begin with.)
I second the advice to read the letter to him. I’m a chicken, too. That’s how I told my True Love that I thought of him as more than just a friend. Now we’re married.
I wrote a letter confessing my feelings to a long-time friend.
I basically said (paraphrasing), “I like you. I think we fit well together in a lot of ways. I just wanted you to know that. Don’t feel pressured to give me an answer right now - take some time to think about how you really feel about me. It’s okay if you don’t feel the same. I still want to be friends, because I value your friendship”.
And we’ll be celebrating our first anniversary of dating in a couple of months. 
Sometimes a letter is the best way to articulate something that needs to be said carefully.
And I also think it is best to give the person a chance to think abut things. If you push them too hard too quickly, they may very well have an urge to panic and run from you.
Good luck.
**Doctor Who’**s advice is perfect.
If you absolutely can’t bear to do what he says, I suggest this as a less desirable, but still okay, approach: next time you see him say, “Hey, we haven’t had a chance to catch up, just the two of us, in a long time. How about if we get together for coffee at Downhome Diner next Thursday after work?” (Whatever - you get the idea: pick a very specific time and place that is no big deal.)
Then, when it is just the two of you, push the conversation toward your relationship and take it from there based on his response. For example:
YOU: We never get a chance to talk anymore, we should get together just the two of us, more often.
HIM: (a) yeah, good idea - OR - (b) true, it’s too bad that my nightschool classes leave me no free time.
or perhaps
YOU: We never hang out together any more - (in a lighthearted tone) - Do you have girlfriend who is taking up all your time? Or are you waiting for someone to come along and ask you out?
HIM: (a) Girlfriend? Hah, hah, me? No, I am completely available. or (b) Funny you should say that, I don’t have a girlfriend but I have been eying a woman in the accounting section at my office.
etc. Of course, I’m writing the above dialogue and in real life, you don’t get to put words in his mouth. But if you come up with a good opener, and a plan for how you will handle any type of response, surely you can open the topic with both subtlety and self-confidence.
But I still like Doctor Who’s approach better. And I think sending a note is setting yourself up for embarrassment. What if it turns out he’s not interested - he’ll have something** in writing **that you will wish you could take back.
One last comment - does this guy date at all? I realize I have no basis on which to judge, but is it possible he’s gay and in the closet? (Back in the bad old days when I was dating, this sort of thing happened sometimes.)
Ask him in person. Read the letter out loud if you have too. Hopefully that will give you the definitive answer, and either way you can quit with this noise and go about not being a chicken. You seem to be continually bargaining with yourself and you should probably stop. It’s enabling your chickendom, the only way to stop being a chicken is to quit making daily choices that slowly encapsulate your personality until you become a clucker. Doing it before a vacation? That’s a horrible egg to drop.
To step up my advice further, I wouldn’t waste time even thinking about this guy romantically anymore.
I thought that it was one of those things people do to reassure others and show interest and acceptance.
If the OP has trouble saying the words, avoid the words or at least, don’t start with them. It sounds to me like there’s been some misdirection here. There’s interest that’s been obscured by dropping the ball a couple of times. Actions speak louder than words, so start with those. If he welcomes the touching, it’s a green light for the words.
Well, I fired off an email after my sister got on my case on why the letter was still sitting on the table. It’s as she told me last night “If you don’t do it today, you’ll never do it.” And she was right… I was holding off on even giving him a letter because I just wanted to put it off and keep this fantasy in my head how someday, maybe everything will fall into place magically without either of us taking different steps than the ones we’ve been taking this whole time.
I get that most of you would have done this in person. But is it so hard for some of you to accept that it’s not how everyone would choose to do it? Or even that it’s the best way for me to do it, given the individual circumstances that I’ve been through with this guy as well as my personal history of romantic relationships? I resent the notion that I’m doing this out of immaturity. Believe me, if I could just spit it out in person, I would have a loooong time ago. It just doesn’t come out of me that way and no amount of egging on and people say “just do it” will enable me to blurt it out when I’m in front on him. And while it’s true that I haven’t figured some things out, I’d like to think that I’ve learned from my past and am now doing the best that I can. I don’t know anyone who doesn’t make mistakes about relationships, romantic or not, so if this is a mistake… then I guess I’ll just have to learn from it. I do appreciate the comments of the people who wouldn’t do it this way themselves, but realize that this is path I choose.
lavenderviolet, I am glad to hear that it worked out for you! I hadn’t thought about how a letter would give him an opportunity to think about what I was putting out there before responding. I mean, I admit that this letter is being sent for rather selfish reasons… that I get to dump my feelings onto his lap and now it’s all on him to get back to me. But I’m not quick on my feet… and neither is he. Maybe he will take this time to sit and read it over and ponder what I’m really trying to get across and have a chance to sort out his own feelings. Or maybe he’ll take the time to craft a proper rejection. I’m not doing this because I want to cling onto him and make him like me if the interest was never there. I’m doing this because this “thing” between us has been going on for way too long and it’s time to just make it clear and if he’s not interested romantically, then at least we know where we stand and make an attempt at friendship.
Your situation sounds very much like the one I found myself in not too long ago, right down to the leaving for a vacation shortly after. Well, except that I’m a guy…
I completely understand not feeling able to say it in person. It’s not like I don’t think that’s the preferred method, but if you aren’t able to force yourself to do it, your only options are sending the email/letter or continuing with the uncertainty and doubt.
I wish you better luck than I had, though we’re still good friends at least.
And for what it’s worth, I don’t regard it as a mistake. But in the unlikely event that it ever happens again, I’ve resolved to say it in person no matter how difficult it seems.
Glad you sent the email, Grapefruit. No offense, but you were totally overthinking things. I’m crossin’ my fingers for ya!
I don’t have a problem with it. I don’t know if it’s been specifically stated in the thread but I assume you’re a woman. If so, you get all kinds of latitude when it comes to doing the asking. I mean, men are raised up to do the asking and develop calluses to deal with the rejection.
I’m glad you did it. One note for future reference: do it sooner next time, before it twists you into a pretzel. The more you like the guy, the more you want to ask but the more you fear the rejection, so don’t let it escalate to that point. You need a pressure release valve in the equation. 
Good luck!
Okay, Grapefruit, you ARE going to give us updates about how this all turns out, right?