Is this a worthy frame to use?

Nice score there... yeah, those 80's Murray frames are nice and strong. Just check the welds at the 2 tube that run from the rear dropouts to the front of the frame... sometimes the welds on this type frame break off at the seat post or front down tube which will lead to it quickly popping the other weld. The good thing about these is that if the welds look weak you can strip the paint off the area and braze the joint up really good, this will ensure the frame is plenty strong enough for daily use at 30+.
You can strip the paint and braze all 4 points as preventative maintenance if you wish before you start riding it daily too, you'll need to re paint it if you do, but it'll make the frame a lot stronger.
Some of these have really nice welds already, but others are just barely tacked on so definitely check these welds as well as the welds at the bottom bracket where the 2 rear triangle tube are connected, this is another weak spot, and this area becomes vulnerable to cracking if the other welds I mentioned above are cracked off.

Nice old frame , should make a good daily driver , good score for 100 , what zip code in TN. are you located ?

I look at the rear drop-outs and just bite my (tongue) lips. When I think of Murray, I think of Bill Murray.....need I say more?

Murray and Huffy are just two manufactures I personally would not try to motorize for myself. Sorry, I just would not~! I have good reason for this.