Just purchased the Academy P38 in 1/48, four in one kit for my 10 year old. Are there any quirks or issues to look out for? The decals seem much thinner that those of other Adademy models I have bought. Do they work all right? He can assemble a model without any problems if it is fairly straight forward.

I didn't have any real issues with mine. I think really about the only thing you might want to get is a resin cockpit (True Details is really nice, and relatively inexpensive) and resin whees (again IMHO True Details' wheels are a good choice).
I didn't have any decal issues that weren't of my own making…
This is my Academy Pathfinder:





The stuff in the nose were bits from the scrap box (Monogram B-17 seat, Monogram P-38M Radar Operator's panel and some miscellaneous EM bits you can't see).

That is a very nice build. I was very impressed by the kit and was thinking I should have purchased two at the same time so I could build one with him. He already has the cockpit assembled and was working on the wheels. He doesn't need resin yet, but when I get the kit, I will take your recommendation.