Hi Scott and welcome to the forum.
the first place I would look is at the edge or the roof. As you look sideways at a mobile home shingle roof near the edge, you will usually see the shingle courses coming down pretty straight, and then when you look at the edge shingles (first course of the roof), you will see a bit of a dip and sometimes the edge of that first shingle will actually flip up just a little bit. This happens with age and is actually caused by the metal drip rail sticking or pointing at a slight up angle in most cases. This can cause a couple of different problems.
1. Rain water can blow under the first course of shingles pretty easily.
2. There is enough of a flip to the shingles where it causes water to run sideways before coming off of the roof.
If the shingles are less than 10 years old and are in good condition, i.e. not brittle, the edges of the shingle show no wear and you do not see the fiberglass scrim layer feathering out from the edge of the shingles, you can remove the bottom 4 course or so and install an 18" wide strip of Ice & Water Shield onto the sheathing, reset the drip rail if needed and reinstall those shingles. This is best done DIY because a contractor's labor in this will greatly increase your cost per foot charge. If a contractor is going to be used, it is better to install a new roof, using the Ice & Water Shield.
There are cheaper techniques out there. Some will try to slather a Blackjack type product under the shingles, but you have to get it up there pretty high. There are also sealants that are advertised that you can put on top of the shingles to try to seal them. I have not found either method to work very good.
Roof ldge leaks are pretty common on mobile home asphalt shingle roofs due to it's low pitch.
This is just the most common edge leak problem I have seen. Without looking at your roof myself, this may not even be your problem. Sorry my suggestion for correcting this type of problem is not cheap or easy. Hopefully someone else might have some ideas.
Today is PERFECT!
All information and advice given is for entertainment and informational purposes only. The person doing the work is solely responsible to insure that their work complies with their local building code and OSHA safety regulations.