97 B2500 with a 5.2 does anyone know how the fuel lines are routed from the tank forward. At first look appear to be hidden, a fuel leak developed above the muffler.

 

I wouldn't think you'd have any fuel lines running over top of the muffler/passenger side of van... is your tank in the rear or the left/driverside? assuming leftside... tail pipe will drip water condensation as will an muffler with cracks and holes, if you sprung a gas leak you'd definitely know it by the overpowering wreak of gas in and around you rig.
My 99 3500 fuel line also seems hidden until it appears coming out from from the (will call it false floor for lack of better word) on the underside but inside of the frame rail (like right under the driver seat) and just about even with the evap canister ( front to rear) placement. This fuel line is a black flex line with a quick connector attached to another black flex line of same size that runs over toward the (driverside) transmission bell housing and meets up with the two evap lines coming over from the canister and electrical lines all bundled together, then go through.
Obviously the fuel line will head up to the fuel rail and the evap lines go (not completely sure) but assume the left fender well under the battery area the the purge solenoid etc.

 

There is a strong gas smell as well a puddle that forms on the drivers side of the transmission when started. It stops when not running are you aware any connections up in the frame rail. Yes there is no problem starting so maybe it is a return line.

 

Could be if the line from the pump top of the tank is metal line, then switches to the flex line somewhere from that point to before it comes into sight where you can see the quick connect... but honestly, I do not know for certain, never have dropped my tank but suspect will at some future point. Wish I had the answer for you but hopefully someone who knows more will chime in...

I'd think if the leak ain't coming from the exposed section ahead of the tank (mentioned earlier) upto the fuel rail atop the intake then ya, it's the line or connection at the top of the tank and pump.
I'm curious, can't you see where exactly that it's dripping from

 

Found that the fuel line is a flex plastic that has a connection from fuel rail to mid way to the tank on the passenger frame rail. The leak came from a combination of heat and friction from sitting on the transmission all these years.