With regards to the overall time for a thru-hike, the end-to-end distance, without the loops, is 96 miles.
We could do 8-10 miles/day very comfortably, 10-12 miles a day on average not slacking off, and 12-15 miles a day if we were pushing it pretty hard. Just figuring 12/day, gives you 8 days. If you can pump out 15 a day, you can probably get it done in 6-7 days.
The trail is pretty well marked on the west end, not too bad on the east, but markers can get somewhat scarce. If you've had a lot of rain, you may have to do a little wading.
I've got
GPS routes (Garmin Mapsource) if you're interested, for the primary trail.
Now is the best time. Hunting season is over so you can camp off the trail wherever you please.
PS...if you get the latest / greatest version of the USGS topos of the area, the trail is marked very well on it.
I've got the CD version of Texas from National Geographic. The trail is marked clearly and I can trace the trail with the route tool and download it to my Garmin eTrex.
rgds,
WestTexas (Class of '88 TAMU BS, '02 MBA)