I basically did something like that, except instead of putting the switch below the foot plate, I put the magnets on the beater and mounted the Rock Band drum base/controller vertically, so that its the beater making and breaking the connection, not the foot plate. I find it works great once you have the sensitivity set right with the magnets.
Anyhow, I haven’t played in awhile, but I’m fine in Expert mode for 90% of the songs, but that Fall Out Boy song kicks my ass. It’s so quirky and jerky. Drives me nuts.
I know you can just make rhythmic mouth noises for the cowbell parts, but I think that’d definitely mess me up on rhythm.
Not to turn this into a hijack, but keep in mind that the tambourine/cowbell parts are BONUS points – you don’t lose anything if you ignore them.
Back to drumming. I love drumming. Have I mentioned how much the drumming rocks? I had some interest in drumming for real a few years back, and I actually own my own real drum set. But I only took three lessons before I had to quit. Still, I love it.
I’ve gotten through the majority of the songs on Hard, but I have a great deal of difficulty with the last tier and the songs that have a lot of off-beats with the bass pedal (it took me a few tries to get through “Vasoline” on hard when I first started it). I’ve also gotten through the first tier on Expert, but I nearly committed suicide over “Mississippi Queen” there. I’m not sure how much better I can get, if it all.
Most of the time these days, we (my wife sings for the mighty Apocalyptic Cheese) just work on getting more fans with slightly easier songs or with the downloaded content we have. “More Than A Feeling” makes us very happy. 
My favorite song to play is probably “Foreplay/Long Time” on Hard even though I can barely survive the beginning. It’s just fun, and when three or four of us get together, I like to stand up and sing backup during the two times when the drums are silent. 
ETA: Oh, I forgot. Yeah, I broke the bass pedal very early on in the process and RMA’d it. I found a guy on the rockband.com forums who fashioned pedal covers out of carbon fiber that you attach to the original pedal with adhesive. We’ve had it since Christmas and it’s been fantastic – we can (and do) pounce on it without fear.
I hate to tell you this, but you should still fear for your pedal. I fabricated my own metal cover for my pedal after I snapped it in half - so it broke at the hinge. The things are just very poorly engineered. It’s a shame, because if they’d put about 50 cents more worth of plastic in the thing and spent another 50 cents on a steel hinge, it would have been fine. But they really cheaped out, and I’ll bet you the RMA costs to them have been at least 10 times what it would have cost to do it right in the first place.
After playing a couple of weeks, I have some other minor complaints, but my main complaint is that the kit seems to be sized too small for me (6’ 2"). I seem to keep trying to maintain awkward positions to hit the centers or my strikes will wander to the top edge of the outer pads. I can’t hook the bass pedal to the kit as that puts me too close, so it’s loose on the floor and tends to float around a bit; eventually I’m sure I’ll do something to lock it down more.
Oh, and my other big complaint is that I had to listen to, much less participate with, REM’s Orange Crush. shiver
Tell me about it, duality72. I’m 6-6, and there’s just no natural combination that I can figure that doesn’t tire something out. I have to sit on three pillows to make it even somewhat natural for me.