Travel somewhere in the USA around the end of April by myself, any suggestions?

Go to Disney World or go to The Smokies.

You should defiantly check out California around the LA county. There are a few interesting things that you can check out like the wax museum, and the Hollywood walk of fame. Oh and the Chinese theater.
Aside from that, perhaps New york, and even Boston has a few historic places you can check out, though I promise there isn't much to Boston.

I'd go to Las Vegas in hopes of seeing Criss Angel....the Mindfreak!