"What other frameworks would you folk recommend I look at"

I would definitely check out Raisin. It seems to be the "new kid in town" and it looks like it is becoming very popular.

"Any other warnings or guidance from those with experience in REST"

Be very mindful of making changes to the API downstream. Many APIs wind up depending on versions because necessary changes to the structure. You would be wise to study existing APIs that are close to the domain you are modeling.

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)