The front over cab window of a class C and pick up camper are notorious areas for leaks, as well as the forward facing clearance lights. Make sure you check that window, pull out the mattress and check the whole area for any water damage. Check for sagging floor above the cab.
Our previous class C had that big window up front. Luckily, in never leaked. But, I had to keep a close eye on that window seal. It would shrink in the heat, and pull away from the window. I had to have it re-sealed a couple times.
I think most RV manufactures have done away with the big forward facing windows.