I wouldn't bother... A replacement RV tub can be had for between $35 and $100 from Ebay depending on the model you need. I wouldn't take it all apart just to put the same one back in.
I had our tub out earlier this year chasing down a ground issue with the outside marker lights.
It wasn't that big of a deal, but I discovered that when they put the screws into our tub to hold it in place, the tub was not fully seated on the bottom support. Every time we stepped in, it squeaked and creaked like mad and as it turns out, there was a crack in the corner up behind the surround that was slowly working its way down towards the lip of the tub. That corner of the tub was sitting 1/2" higher than it should have, so you can imagine how much it was flexing every time we used it.
When I reinstalled it, I made sure the tub was sitting flat on the floor before I screwed it in place, and made sure I used some high quality marine-grade sealant on the existing crack. The tub doesn't flex at all when we use it any more (and therefore, doesn't creak and squeak either).
So, all that being said, I'd just replace it. It's not a difficult job at all. On a shade-tree mechanic's scale of 1-10, I'd put around a 3.5. Remove the faucet, remove the surround, disconnect the drain pipe, remove the screws holding it in place (probably 3 or 4) and it pulls right out!
