I have a Lance-Lite 815. The "-Lite" means it has thinner walls and less amenities to reduce weight. With thinner walls, less room for insulation.
I don't have thermal windows, but for winter I do have foam boards I put in the windows in the cabover and acrylic panes I put in the windows by the dinette. While not as good as thermal pane windows, the acrylic makes a noticeable difference and much more comfortable.
Some better campers would be the four season campers. These include Bigfoot, Northern-Lite, Adventurer and others. Even the newer Lance (non-Lite) campers are much better.
Usually, when boondocking, I usually drive around during the day to recharge my batteries, combined with I don't have TV, radio or other electrical devices, so my single battery without solar works well. If you plan on staying put for several days or want to watch TV or run small electrical appliances with an inverter, you should look for units with dual batteries and possibly even some solar.