Well, I decided to bite the bullet. I ordered a 25 watt folding solar panel for the TD.
https://www.21st-century-goods.com/product/Sunlinq-25-Watt-Folding-Solar-Panel.html. This was the cheapest with no shipping. We use very little power when camping, and are rarely at civilized campgrounds with shore power. We have never gone below 1/2 on our battery in one weekend, even when using the DVD player, but with our first week long trip coming up, I wanted some insurance. I know it won't recharge a dead or dying battery, but a trickle charge to keep it up/top it off for our slight useage maybe all we need. Trying it out in two weeks (if it gets here in time) and I'll let you know!

. They are still pretty pricey at $300, but I so like the idea of solar, and portable, it is worth the investment it to me.