Peter will have substantial lines, no benefit to going there first. The line will remain the same pretty much all day, so you might as well go on that later when the lines for other rides are long. But really, with an 8am opening, any other ride will have short lines. Space is probably the one exception, but even that will be lighter than later in the day. Grab a FP for whatever ride you want and head to anything else you want to ride. My strategy is usually to grab an Indy FP and head to BTMRR and ride it a couple times before there is a line. Or sometimes we go to Fantasyland and ride everything except for Peter.