Does it have a gauge?
If it's been sitting awhile it may take a bit for fresh propane to get up to the fridge, stove etc. especially if the tank valve is kept off while sitting.
Our last RV had a leak. We could smell it outside a little if we were parked and no breeze or wind. Definitely something to NOT take lightly. I found it just by crawling around underneath it and looking for loose connections etc and found a line rubbed against the frame creating a hole. Just spliced in a fresh piece of line - and of course re-routed it to not rub anymore.
Like Spencer said, You can mix a little dish soap (couple drops) with water in a spray bottle, just spray it on suspect areas and watch for little bubbles. If the coach is older, also spray the rubber flex lines, its possible they can dry-rot & crack.
hope this helps.