Are you able to skip Part 2, then come back to it to reap the actual rewards of doing it?

Obviously this section is difficult, but clearly it's worth going through with it still. I'm mostly wondering because I think the tactical way to do it without too much suffering is to use some of the later boons like discounted blessing and higher exp gain, which get better with more routes done. But the route completion rewards like side quests and map filling that makes Part 1 less tedious haven't kicked in yet (presumably not until Part 2 ends and I bring my lord to the present.)

I'm also wondering about if you could kinda "save" your Part 2 playthrough, so you don't have to do the entire start again if you do come back to it after skipping. (I've already beaten the first and can probably do Chapter 2 with another try. I don't want to erase my effort or have to do it again later.)