Yeah, I know what you mean about a Multi-part fic...the problem is that if you haven't plotted for it beforehand, its VERY difficult to write as you get bored easily.
Whenever I start a multi-part, I tend to write 2 pages of plotline 1st - THEN the story just flows out of you.
Hmm, if you'd like to write another R/H fluff, here's a little one shot which could be done:
When Ron is poisoned in HBP and in the Hosp. Wing, he's calling out Herm's name...
You could do a scene where Herm comes to visit him after hours and they talk...(That could be the reason for Hermione smiling so widely whenever Lavender came up to won-won when he recovers) 😈