15" Wheels.

If it was me I would take the front and rear wheels and tires off one side of the dart. Especially the front. Mount the Dodge truck wheel by using a couple of lug nuts and look and see if there is any clearance issues. Turn the steering to the lock and see how much clearances you have. Turn it to the other lock and check. (All the way left and then all the way right)
If the wheel works out now you get to chose which tires will work and not have clearance issues. :)