I have a mobile home with ugly vinal/wallpaper coated drywall. I want to paint over this instead of replacing all the drywall. How do I do this & what do I use?

When I had a decorating problem like that I painted over with Zinser's Bullseye l 2 3. In some cases just one coat and you can paint over right away. Read about it on this website:

Decorating Direct - UK (http://www.decoratingdirect.co.uk)

I have done this joba a few times for customers... It isn't fun... Heres what I did.
First, take all the plastic strips off the walls to be painted. Take a hammer and a nail set, and lightly pound all the exposed nails back in to the walls. Now, push on all joints and corners to make sure all the walls are still nailed tight to the studs ( I think they are 2x2's) If some areas are loose, use some drywall screws and screw the areas tightly to the studs. Now, instead of drywall taping the seams, I have used a lightweight filler instead (light weight filler doesn't shrink) . The one I use is called "Shur-patch" I would get the 1/2 gallon tub. Use it straight out of the container without thinning with water. Take a 4"-6" putty knife and pack the shur-patch into the seams where the plastic strips wereOnce completely filles, take your "clean " puty knife and wipe all excess filler completely off the wall leaving only the tightly packed filler in the gap ( where the strips were) You can do inside corners this way also, if you take your time. A painted wooded corner moulding works good on the outside corners, and a wooden quarter round ( or similar) works also for inside corners if you don't want to fill them. The key with the shur patch is to pack it in tight and wipe it off because it doesn't sand easy. Let the shurpatch dry at least for a day. Now go over all your seams, gaps and nail/screw holes with normal drywall filler and applying a thin coat. Use a 6" putty knife the first coat, ( let dry) then the next coat use a 12" putty knife and go over all your seams again with a thin coat. ( just like taping) Let dry completely. Then using a sponge sander, ( fine grits) lightly sand all your areas down and if necessary you can re-fill any flaws if you have some. When yor happy with all your prep, use the BIN 1-2-3 and completely prime all your areas. For the best finish, so your vinyl walls resemble drywal lpainted walls, use Benjamine Moores "Aura" paint. It lays down and levels very nice. I have used other brands, and you still completely don't get rid of the vinyl look, although it still llooks good."Aura" paint is the way to go... If you don't mind keeping all the plastic strips up, just prime and paint and your done...

I did this in my house, used Zinsser Gardz High Performance Sealer over the paper, it is recommended for covering wallpaper. It is latex and drys hard and moisture resistant. Let that dry, go over the seams with a drywall compound if necessary (you could do this before the primer as well). Then paint. Simple and looks good. If the seams are bad, use a razor blade to scrape them smooth.

Primer Sealers from Zinsser - drywall primer, exterior paint primer (http://www.zinsser.com/subcat.asp?categoryid=1)