The front door needs to be replaced. As the place has settled, as the screen door was left propped open for (years), it's pulled the door out of true. Easiest fix, replace the door. Hard part: getting out to actually purchase the door. Real Soon Now.
The back door needs to be replaced too, but as it opens to a roofed porch, it isn't as exposed to weather; mostly it leaks AC/Heat.
Then there's the floor. Being a 24 year old mobile, it's particle board sub-flooring. Last summer was damp and humid enough, and the vapor barrier underneath the place torn up by raccoons and possum enough, that the flooring started to warp in the kitchen. The fix is relatively easy; new vapor barrier on top of the old floor, and then tongue and groove plywood flooring down on top of that. Probably three or four full days work, to pull old carpet, lay the vapor barrier, and put down the ply.
Now, to do it.