EXACT same situation with me, except it was 300 kms. Hamilton, Ontario to the University of Windsor. She neglected to tell me about her boyfriend.
130 miles when I was having a long distance relationship. We are now married.
About a thousand miles, from Tennessee to Montreal. It wasn’t a sure thing as we were just friends but she knew I liked her and we had talked about it. It wasn’t meant to be, though, and I wound up leaving three days into my week there and she severed all contact with me shortly thereafter.
I tried calling and IMing to find out what I did but she never would tell me and I stopped trying after the second attempt. Too bad, too . . . she was gorgeous and a good friend while we were still on good terms.
About 110-115 miles. Not all that far, really.
But it was on a motorcycle.
In winter.
And she lived in the freakin’ Sierra Nevada (well, the foothills). Have you ever ridden a motorcycle right after a snowstorm? I must have been crazy.
Fortunately, she was crazy, too. Didn’t last long, but the saying is true: crazy sex is the BEST sex.
My husband travels a lot for work…months at a time, only coming home on weekends. If his assignment is someplace interesting, I’ll go out to see him for the weekend instead of him coming home. So, I would say from Chicago to Washington DC, Richmond, VA, or Denver, CO, whichever one is farthest, would be the farthest I have gone.
Of course, the trips were more for the sightseeing than for the sex…so I don’t know if this counts! 
I flew from Frankfurt, Germany to Thailand to get me some of that sweet Thai loving.
My wife and kids were already in Thailand ahead of me, your perverts.
For me, it was about 56 miles, but the procedure was quite unusual.
I was living in Doncaster, in South Yorkshire, England. I was working behind the bar of the town’s Rugby League Club, a very working-class establishment in a part of town where half the folks were coal miners and the other half were unemployed coal miners, or so it seemed.
I was 21, and there was a woman my own age working behind the bar with me, and she and i were sleeping together. We had to keep it quiet, though, because she was living with her boyfriend, and news travels quickly in small communities like that. (And, no, i’m not especially proud of it; i was 21 and thinking with my dick a lot of the time.)
Anyway, sex at her place was obviously out. I lived about 14 miles out of town, in a small village to the east of Doncaster. She didn’t have a car, and i did, so on the evenings when we weren’t working and when she could get out of the house (using the excuse of “goin’ out wit’ lasses”), i would drive into town, pick her up, drive back to my place where we’d fool around for a few hours, and then drive her back into town before returning home for the night.
On the nights when we were working, things were much easier, but also less comfortable. I’d give her a lift home, and we’d do it in the front or back seat of my car. Sometimes in the club parking lot, sometimes parked by the kerb in front of her house.
Rochester, England to Victoria, BC, Canada. Although that was a distance relationship and I am now married to the woman in question.
Great Circle Mapper makes that somewhere just about 4800 miles.
Boston --> The Netherlands.
Was going out with a chick studying abroad for a semester. Don’t recommend it.
Don’t tell me you stopped stalking that Asian girl already.
Holiday Inn? :dubious:
I’ll have you know I stayed at the Wingate my good fellow.
I’m not one for scrimping 
Similar here. I went to Chicago on a promise - a girl there considered me a handsome devil from our stolen kiss when she came over to see one of my friends. She even paid for my ticket. But as it was a few months in arranging, by the time I actually arrived, she was ‘seeing’ this chubby, flatulent electrician who reminded her of Billy Corgan from the Smashing Pumpkins.
So I just went on a pub crawl for the next two weeks, and slept with her friend instead. 
Omaha to Johnstown PA (and back) in a 3cyl Subaru Justy with no radio.
If we want to talk about the longest trip rather than the farthest, it would have to be the half mile I walked while in college in Fairbanks, Alaska. My girlfriend promised sweetness if I went for french fries for her. It was -63 degrees F. I frostbit both ears. Longest hike of my life.
Long distance is the story of my life. I’ve had several girlfriends who I had to travel 100 miles or more to see, and my wife and I still can’t live together full time because of our jobs. She stays with her mother, who lives close to the dance studio, 3 days a week and makes the 100 mile+ trip to our place when she’s done for the week. I did that trip for about 4 years while we were dating.
The longest single trip was probably about 6,000 miles to see my ex-girlfriend, several years back when I first came to Japan. We were officially broken up because I didn’t expect her to wait until I got back from overseas, but still had feelings for each other. I hadn’t had sex in over six months, and was pining for her anyway since I’d been with her for almost two years and didn’t really want to be apart from her. It was a very intense visit. We broke up for good several months later, partly because I wanted to stay longer than a year. Technically, it wasn’t just travel for a sure thing, but sex was part of it.
Well, about 70 miles for a probable hookup. But then we started dating, and I regularly drove about 210 miles for a few months.
Ask me in a week or so, and the answer will be 7861.5 miles.
A little more than 35K feet, back in 1960, for a quickie.
2400 miles, from LA to Ohio, when I went to meet my LDR sweetie face-to-face for the first time. I can’t speak for him, but I’d be lying if I said I flew over there without intending to make a move.
These days, he’s usually only as far as the other end of the living room.
About 7,000 miles from the Bay Area to Sai gon, Viet Nam and with an old high school girl friend.