Gallery posts have always compressed, general attachments will compress as of 7.6.1 (once it's out the door anyhow). It will only affect new uploads; you could use something like JPEGMini to compress old attachments.
As for gallery/attachments settings we always recommend ImageMagick over GD as it produces clearer images; the defaults as of 7.6 are 125, 480, 1920 pixels; 80% 70% 60% quiality
And TY, it was a fun trip last week, luckly I didn't throw my back out until AFTER we got home, lol.
