Finally ordered this:
http://www.amazon.com/Leviton-Mounting- ... receptacle
Nema L14-20 receptacle.
AJ came over on Saturday to drop off a hole saw/arbor and gave me a few additional options to consider for getting the outlet on the generator. There are 3 main options, and all involve the outlet, which is why I ordered it:
1. Drill a 1-9/16" hole in the front panel and two small mounting holes. Install the outlet right on the front panel next to the old Nema 6-15 240V outlets.
Pros: Most "native" installation
Cons: Still tracking down a 1-9/16" hole saw but 1-1/2" and some grinding/filing should work as well. Also defaces the front panel which oddly I actually care about.
The next two are derivations of the overall electrical box concept.
2. Install outlet in a weatherproof box and mount that directly on the face of the front panel.
Pros: No need for a 1-9/16" hole saw. Fewer holes in the front panel overall (could probably get away with putting it back to stock)
Cons: Looks tacked on (because it is literally tacked on), protrudes from the overall footprint of the unit
3. Install outlet in a weatherproof box and remotely mount that somewhere on the generator, but not directly on the front panel.
Pros: No drilling in the front of the panel (holes would be basically hidden on the bottom, going back to stock easiest of all options)
Cons: Even more tacked on? More work.
For all of the options, I think extending the 240V wires is going to be part of the job which I was hoping to avoid. I need to pull the panel apart again and see just how much wire there is, even if I had to cut the little wire ties that are bundling everything together.
I also need to tackle the house side, starting with ordering the correct Nema L14-20 weatherproof box that I will mount on my house.
Alternate plan: convert my old dryer plug adapter into something that will take input from each of the two 120V outlets and backfeed 240V, instead of backfeeding 120V as I have done before. That will require buying another 12ga extension cord which is probably the cost of the box that goes on the house. I should just move toward doing this right.
Really lame alternate plan: Just run 120V into my dryer plug adapter which would give me ~2000W instead of the 1500W that I usually get from my inverter (and Caprice). It would be far quicker/easier to setup, use less gas, but be noisier. It also, critically, wouldn't power the well pump, which is really the only reason I even need 240V in the first place.