If you really want a float section you can put in at the take out of the Box (Taos junction Bridge- TJB) and float 5 miles (with 2 class II rapids ) down to quartzite- the put in for the Race course, or combine them for a longer day. We do that on commercial trips when the water is up to make the trip actually last long enough. (really half ,from lone juniper put in.) there is good pay camping in that section, from next to TJB down to lone juniper. you could then finish the box by floating to camp. pretty sweet! watch out for poison Ivy in the Box and around the last rapid (Sunset) at the confluence of the Rio Pueblo. theres ACRES of it on the first half of the box. all float up there though- no need to be on the bank. theres also lots of bighorn nowadays.
The LTB is really technical under 1000cfs and a 12' raft is much better, or tupperware. also Rowing at that level is pretty tough. we (the company i work for) cut off trips at about 700 or below. it can be kayaked down to 400-600 but its bony and a loooong day. can hike/lower/climb kayaks into powerline too, but its fairly epic. unless you like challenges like that :]
the 'teens' 1500-2500 is maybe a more difficult but fun level. the rapids are not washed out, have big holes and all the features are in full effect, but its still technical it gets really big around 3000 but cleaner. thats one of my favorite levels. powerline is HUGE at 3-4000cfs .. Powerline sort of flattens out at higher levels. the highest i guided it was at 6000 cfs in 2005. the highest i have kayaked it is 1500. I always cautious every time i go in there because its one way in and out...pretty much. there is usually always people to follow. its really better to not do a one boat trip, in case of a rescue situation.you can call an outfitter to join a trip, but there will be privates every day if the water is still up.
The most serious part of the box is the last 1/3 or 6-ish miles from powerline down. 'the hour of power'. it gets pretty continuous, more so then Browns, more like the Royal Gorge but maybe more technical. So the list is:
From John Dunn bridge
float (by 2 hot springs )
Mile 4-ish: Ski jump III+
High Bridge rapid AKA Trash rapid. III-
Yellow Bank III+ (IV at low water)
Playground class II-III @ 6 miles
Dead Car Class III-IV
Powerline falls III-IV
Pinball/Rockgarden Class IV w/ V- consequence (depending who you ask.) sieve bottom right- this is the toughest rapid IMO. Move R-L !
boogie water/Cathy's Cleaver II-III
Boat Reamer III-IV
Punk Rock/ Screaming Left/Rio Bravo /Screaming Right (@ 1 mile long continuous class IV section.)
Float for a mile
State Park float 5 miles
Race course/Pilar run 5-6 miles class II-III (IV > 4000cfs)
Taos county line Takeout
Embudo float 8 miles- ish.
White rock float
So I i would definitely recommend doing it, but go with someone who knows the lines, and it will be a pleasant time.
Hopefully this helps as a rough guide for you. theres of course different opinons on the difficulty, but as a class III/IV- kayaker I dont think i am sandbagging it. its challenging for me. i am more comfortable guiding a raft then kayaking, at high water for sure, or i was last time it was huge,but i am working on that...:]
hope the water sticks around, but its really warming up here.the the Rio is friggin sweet right now...!