Hi my name is Robert...
I can give you an idea on the labor for each, it will be ball park....
The windows being sealed, depends if they are going to be removed or not. The window will have a foam gasket that presses up against the sidewall of the RV, many times you can just mask off each window and use some clear silicone where the window frame meets the body, a shop will charge about 1/2 hour to seal each window, if the window is being removed and that gasket replaced you are looking at an extra 1/2 hour per window, maybe 1 1/2 hours.
If all the floor covering needs to be replaced you are looking at about 3 days of labor or 24 hours, many times items have to be removed and then re-installed when the carpeting is down.
IF you are talking about all the wall board that would also be about 3 days or 24 hours of labor.
Winter skirting will cost about 6 dollars per foot so you would have to double each side and then front and back so on a 34' coach you would be paying for about 80'x 6 dollars.
It adds up for sure ball park on this you are looking at around 50 hours, most shops charge 100 a hour some charge less so it is smart to shop around and see what the labor rate is..
I would say total you are looking at around 5K to 7K to get it all in shape. I would have at least three shops give you an estimate... In my opinion it might not worth having the RV fixed up due to it's age but on the flip side you should be able to recoup some of that money if the RV is sold.
IF you have more questions or concerns please feel free to contact me. Please keep in mind I only get credit when you select a rating at the top of the page.... Robert