3 different exterior keys really needed?

We have two exterior doors each with a different key and the pass-through slam latches have the same style of key. Is there any necessary reason for this? Maybe it's because it's cheaper and less hassle for the TT manufacturer to do it that way.

I'd like to get the locks re-keyed to match so I only have to carry one key around. I can't see a problem as long as I don't change the one on the main entry door so that a dealer can still get in? It's also annoying to have to keep looking at the number on the key to make sure I have the right one the first time.

There's also a 4th key - the exterior shower door but that's easy to just keep inside.