On the other hand, if I am currently researching and publishing at a near-R1 pace from my 4/4 regional job, is it possible to expect my quality of life and family time could actually improve by moving to an institution with more research support and lower teaching loads?
This is the key information. If are publishing in both quality and quantity at a near-R1 pace with a 4/4 load, then your future is bright that you will succeed at an R1. Having been employed at a R2 and R1, I was busy at the R2 but a different kind of busy. Student handholding was expected. I also warmed chairs in committees. And while some R2 faculty understood the implications of a high-quality publications, others didn't and some how equated Journal of Prestigious and Selective with mediocre fare.
Some years ago, I managed to publish in a cross-discipline major journal. Folks at the top schools solemnly understood the achievement. Faculty at middling institutions were unimpressed. This is not because they were so smart as to find the journal easy pickings, but they hardly were familiar with the journal's existence let alone the effort and tools necessary to publish in it.
FWIW, you seem to have the capacity to perform at an R1. You might find it not only intellectually stimulating, but also liberating.