What changes would I need to make to replace a normal house toilet to a rv toilet as there is no running water in my mobile and I believe it would be a great solution.

Do you mean a composting toilet? (I'm pretty sure that normal recreational campers use toilets that do require water - we've had three (campers), and they all had toilets that required water, so I'm assuming this is what you're looking for?) Here's a link with some info, I only glanced at it, but it looks like it requires A LOT of maintenance - also does not sound like something you would want IN your home - just my opinion, good luck!
Composting Toilet System (http://www.cefns.nau.edu/Projects/WDP/resources/treatmentsyst/Compost.htm)

If you are talking about a camping type self contained unit, it's easy. Remove the old toilet, put a plywood plate over the hole and caulk, build a small platform and set the camper toilet on that. After it need to be dumped, separate the units and dump the bottom. The other solution is to cut the old drain out, turn the new connector to the outside and dump it into a rolling holdng tank. Where are you planning to dump the waste?

Thanks for your reply. I have been dumping it twice a year at a nearby camping ground where they have a spot to do so as I had one in the trailer I used prior to this. After removing the house toilet I noticed the hole in the plywood is to big so I see I have to replace a piece of the plywood and cut a smaller hole. The toilet is a foot peddle flush and you can pour water down it manually. I was asking to see if there were any tips I might get but it seems that I will figure it out. Thanks again

You are already on the way. Hooking up to the outside drain is the best way but make sure you seal the piping so the smell doesn't get past the toilet. Good luck!