For item #2 - you can buy inexpensive IR "eyes" on a cable that allow you to put the receiver in the cabinet and use the remote with cabinet closed. You just need to have the extension mounted outside the cabinet. There are a bunch of different products on Amazon and elsewhere. $15 should get you what you need.
On the Coleman grill, I don't have a picture handy, but if you look closely at the regulator assembly, it is actually two pieces with a threaded connection between the regulator and the part that attaches to the burner. If you unscrew that, you have (I think) a 1/8" npt thread that you can add fittings to so that it will connect to your low pressure LP line. Be careful when you unscrew it - there are some small parts including a spring on the regulator side...
