Option 1 was what I did on C2C couple years back. Well Newtonmore to Ballater, but guts are the same.
I found it a lovely route; there was a minor hiccup (bridge out) in getting over to Glen Feshie, and the track through the Glen Feshie watershed can be lovely or a nightmare depending on how wet it’s been, but it was the longest section of our C2C and was well worth it. Couple of tricky sections as far as taking the right path / line in Glen Feshie is concerned, can end up on the ‘wrong’ side very easily!
Have also done the section from Glenmore round past Tomintoul and southwards as part of a Tour de Cairngorms – navigation isn’t a problem, river crossings aren’t really a problem but would say it’s more of a doubletrack slog for the most part, and the climb over from Tomintoul to Braemar / Invercauld is a killer.
Carrying on past Braemar we headed through the forest to Ballater and then South