Just thought I'd throw in my 2 cents.  My friend always uses a crate.  But she takes the top off.  Mom can get in and out, and it is cozy for puppies.  Every now and then she gives it a good cleaning, which is easy cause it is all plastice.  They are easy to take apart and put back together when you are done.  I, myself, just cut down a cardboard box, but anything will work. 
