PA to CA Journey - New Orleans, LA, Started to have concerns ~300mi ago; "stuck" in NoLA Options

[MAGutz]

First thing's first: Thank you. This website has given me everything that I have ever needed when it comes to my 6GC (of which I've unfortunately, or fortunately!, owned four of).

Secondly, if you're available and in the area, your help could potentially be the most valuable! Seeing problems in person make solving them nearly trivial.

Thirdly, and lastly, my situation:

**NOTE** I've had an "issue" with my car during startup; engine SOMETIMES runs at low RPMs (100-200) until put in drive and accelerated quickly. Sounds like the engine can't breath and the throttle plate isn't opening fully. Also aware of small oil leak; levels still good after driving 2,000 miles.

Roughly three hundred (300) miles ago, I pulled up to a gas station in Mississippi and found myself waiting a moment as all the pumps were currently in use. I decided to put my vehicle in park, as well as turn off the A/C, and suddenly my car turned off. Tried to start her up again instantaneously after, but to no avail. Went inside, bought some gas, filled her up, and waited a moment. When I checked underneath my car, some water was dripping from around the front passenger axle, but no other sorts of fluids. Three hundred miles later, got to New Orleans and took a look at my engine. I was able to diagnose that there was a problem with my radiator as one, I had oil in my coolant, and two, my coolant levels had to be replenished (1L per 120mi). I took her to a local mechanic that I was referred to and their diagnosis and solution was "needs a radiator, thermostat, cooling hoses and system flush." All good there, but when it came to how much it all was going to cost, I questioned the over $600.00 that I was going to be charged for JUST the radiator (excluding labor and other necessary replacements). So now I'm here asking you all for some advice/help.

My next destination is Austin, TX (500 miles away) and there I can actually work on my car with my father, another self-taught mechanic, and give her some real TLC. My plan was to order some OEM parts from PartzNet, flush the system with distilled water, install a new radiator, cap, hoses and thermostat, then drive to Austin. Suggestions? Comments or concerns? What would YOU do in this scenario?