New layout, need motor

Bought a small layout which is only rated for 2 hp. Tracts great, and paddles easy, just slow. Thinking I could use a motor to speed things up. Old trolling motor is fried, so other than a heavy battery I am starting over. Don't want a lot of weight hanging on they back, as it could make dog area under water, so true mud motor is not an option. So here are what I see as options
1. Buy new trolling motor and go a little faster, but deal with a big battery in cockpit with me (there any super light batteries that would give any range?)
2. Build weed eater long tail. Like this idea, but every thing I find on interwebz is from 2005-2012 or so. Do this really work, last or was that a fad and nobody tries anymore.
3. Buy a 2 is hp outboards from Yamaha, Honda etc. Don't like cost
4. Buy a air cooled outboard http://www.ioutboardmotors.com/2015-25-hp-2-stroke.html. little skeptical of how this would hold up.
5. Keep paddling?????????

Do have a couple spots that I don't think I would want to paddle into, as well as a motor would make things easier. Any options I am missing. Thoughts?

 

Layout is locally made carbon fiber boat. Mack's sells them as duck busters I think. Got a transom made up, took set up seat out, built blind, and have it as a true layout. Only concerns I have about a true mud motor is weight on back end, sinking dog area. Of course I could add a raised platform for mutt, but it would add more weight. Got the boat because of easy of the light weight. Also, what about mr. Green jeans and a 6.5 hp motor on boat rated for 2 hp? Would 6.5 be any good on 1436 jon?