Well, I guess I have a few questions.
1. What roelplaying opportunities are there in the module?
Quite a few. The idea of the adventure (which is for 2nd level adventurers, btw, although there are notes for 1st level PCs) is that the PCs have come to the ruins of Spellgard looking for the spirit that dwells there - a prophetess. (Exactly what questions they want answered is up to you and your players; there are suggestions but it's really up to you).
They're not alone in looking for the spirit. There are also a bunch of rival adventurers and other seekers camped in the ruins in an impromptu town. So, that gives one avenue of roleplaying to begin with.
A sidebar on page 9 of Book 2 gives options for negotiating with the first group of enemies (the first encounter always begins with roleplaying). A sidebar on page 13 gives notes for interrogations in the same area.
The second section of the adventure is mostly against mindless undead, so few roleplaying opportunities there!
The third section has more human/demi-human enemies; notes for interacting with them are given in a sidebar on page 47. One encounter begins with roleplaying.
2. How easy would it be to snatch it out of the FR, as I have no desire to run an FR game...or buy the FR books.
Easy.
3. Would you consider this or KotS better as a second try for some people who aren't really feeling 4e (I'm wondering if perhaps I don't have 4e adventure design down and figure I'll try running this or H1)?
Hmm. Possibly this one, but I really don't know. So much depends on how it is run. A DM could have a *lot* of fun with the NPCs in the base camp; but that's true of Keep on the Shadowfell as well.
4. About how long would it take to play through this module?
There are 35 encounters described in the adventure. Assume 1 hour per encounter; even if each encounter doesn't take that long, roleplaying and other activities do eat up time. (Keep was shorter, IIRC)
5. What is the general premise behind this module?
See my answer to #1. The general structure of the adventure is linear: you deal with area #1, which leads you to the clues to reach area #2, which then has the access to area 3. Within each area, #3 is most linear and #2 is most varied.
Cheers!