I've been to Key West several times - it's one of my favourite places. However, there are a couple of things you should know.
1. It's not cheap. During offseason a hotel room the size of a closet goes for ~250 USD a night, and march break is a busy time, so it'll be way more. A more economical option is to look for a B&B or AirBnB for a room, but still expect well north of $150 a night. And book well in advance.
2. There is, as far as I know, only one camp site on the island. Last I checked a tent site went for $60 a night, and because the island is made of coral, putting stakes down can be tough. A freestanding tent works, or there are some pegs that work with beanbags. However, the main drag (Duval) is only a short bus ride away.
3. If you have a small bike you can find places to park it on the island, but you'll have a tough time with larger bikes. Best to leave the bike and bus/walk it - it's a very, very walkable island because it's so small.
4. A cheaper option is to go to one of the smaller keys - Largo for example. Not much to do on some of them, but you can ride into Key West if you really want. You just can't party, if that's your thing. I'm not sure if taxis run between keys.
5. Key West is an amazing place, but it honestly sucks as a motorcycling destination. The highway that runs from the mainland looks cool, but the reality is that it's a couple of hours of straight line with barriers so high that you can't even really see the ocean. The speed limit is 30 mph, everyone is doing 20 and there's literally no possible way to pass. Best to pull off somewhere with a view and chill for a bit.
I'm not saying don't do it - but it's 2 days of pretty hard work to get there on a motorcycle at that time of year. Take enough time while you're there to make it worth it.