SATCHMO

Well, there are two ways of answering your question. The first is, You don't, that is, you don't play solos rhythmically. The understanding of a guitar solo, at least in rock and roll culture, is that it's a single-string quasi-improvisation on the dominant melodic theme of the song, so to play a song rhythmically would really be the equivalent of playing a bridge, in other words, instead of playing a single string guitar solo, you're changing up the chord progression for 12-24 bars, but what that basically gives you is more like a bridge than a guitar solo, even though you may not be using it to lead into another part of the song. As an example, check out Memphis, Tennessee by Chuck Berry and see what he does at around 1:20 in this video:



Another answer to you question is, You don't, as in you don't play guitar solos at all, which is what a lot of two-pieces resort to. Guitar solos really only sound good when there's another instrument carrying the harmonic progression of the song, and they sound especially crappy when the guitar solos are improvised, because it makes it sound like the song has absolutely no direction and there isn't any opportunity to for the drummer to lend structure to the song by accenting certain key points of the solo. Improvised guitar solos + two-piece guitar and drums ensembles almost always equals a train wreck. I really don't recommend it. I'd say rearrange your songs to have either, no solos, or preplanned, well defined solos, or bring another musician into the band to play bass, rhythm guitar or keyboards-- anything that can hold down the chord progression, because the recipe that you're going with is almost impossible to make sound good.