While every store may have AA batteries, to get any decent run times with the new high power lights out you need to run Energizer Lithiums which are not at every store.
I have a Quark AA Turbo Warm White XP-G and love it for around the house. But out hunting I use exclusively CR123 lights. They run 18650 and 17670 as their primary because of the long run times.
If by chance I did run the batteries out then I have 8 CR123 batteries in my pack as extras. With that many batteries I could run the lights all night long for several days. Depending on the level of course.
Walking in the brush I rarely carry my T20C2 MKII because it is very focused with the R2 drop in module. The R5 module has more spill, but either way the light is too much of a thrower to use for trails.
I typically use a Warm White Quark 123^2 for walking on the trails because of the naturally brighter spill of the light since it is more of a flood style than throw.
In your case if you are in a boat searching for logs and other stuff you don't want to hit, then your going to need a good thrower. Also, at times on the water there may be somewhat of a fog to penetrate depending on the weather and water temperature.
I would recommend the Eagletac T20C2 MKII due to its ability to easily reach your 100 yard mark. If you were satified with the lower lumen TK20, then I'm sure you will like the Eagletac.
Also, the TK20 was more of an outdoors light with a more neutral to warm temperature. Identifying logs, a neutral light would probably help. With the Eagletac you can now get 2 different Neutral drop in replacement modules. So you can really find what you like best.
I don't know what other hunting you may do, but the Red LED module they have for the T20C2 MKII is pretty Awesome as well. I have it setup on my bow for night hog hunting.