Wow! How fantastic to hear that you played the Goldberg Variations. That must have been one helluva thing!
Anyway, I wouldn't really recommend this unless you happen to have the resources, but once I saw the Goldbergs performed twice--once on a harpsichord and once on a Steinway D, with a lecture before and a lecture between the two (after an intermission). You might not believe it, but it was a surprisingly effective recital! No repeats, though, thank goodness--except maybe one or two spots, if any.
However, for the variations I have considered a few different recitals, though I probably will never be able to play any of them. First, I thought it would be super neat to program the Goldbergs in the first half and the Rzewski Vars in the second half, for a pretty extreme contrast in styles, but with comparable brilliance in each piece. But, it would also be extremely rigorous for a non-musical audience of any degree (not to say that the Goldberg Vars alone isn't, but at least it's shorter, and of course as with all var. sets, it's easy to listen to because there are so many "different" pieces, which I theorise makes it easier for a non-musical crowd to listen to, although the musicians of course will appreciate that each "piece" is not in itself different). You *might* consider starting with Rzewski and then playing the Goldberg Vars, but my instinct tells me it should be in chronological order not only because of the historical significance but because of the mood and statements of each piece.
Generally, I would avoid doing any more Bach, though. If I wanted to do so, I would probably play a program that consisted of some two- and three-part inventions, French Suites, possibly a toccata, and maybe something a little more dramatic like the Bach/Marcello Oboe Concerto in D minor (BWV 974)--no P&Fs of course. And, personally I would steer clear of that particular Busoni transcription, although maybe something like the D major, Eb major, or indeed C major Bach/Busoni organ pieces would not be such a bad idea.
However, I still wouldn't use Bach as a first choice of contrast for the program. Maybe even if you just went to other Baroque composers like Scarlatti, Couperin, or Handel (I'm thinking keyboard suites), all of whom, again, have very agreeable and "engaging" pieces, as in, they are not necessarily fugues, canons, and so forth, which will inevitably grate on a non-musical mind (though, certainly for us we could probably listen to/play them for hours, but then that's just bragging!). A Haydn sonata could fit in nicely too, if properly chosen (don't have any off the top of my head). If any of those options were chosen--a brief example is a program starting with two Scarlatti sonatas, a few Couperin pieces and a Haydn sonata--I would keep the first half fairly short and light and then, indeed, use the Goldberg Variations in the second half.
Finally, I do believe that the Vars./Op. 111 by Beethoven could work fairly well in a recital without running the risk of "overdoing" it. Op. 111 would be the second half in that case, and no encore would be required, although it could be a neat idea to play a "pre-recital" encore to set the stage, if you'd like, perhaps with a charming little Couperin piece or a trifle by Krebs or Rameau or...whomever. Might be kind of a neat idea...just a 2-minute long fling before the Aria starts, to get everyone settled.
Topic: What do I program with the Goldberg Variations?