100 watts is enough to charge the batteries if you use them fairly lightly in the summer.
We lived without hookups on a 130 watt solar panel for a full year in our 27' TT, and in the summertime, using just one laptop between us and watching just a little TV, we were fine. In the winter it wasn't enough, so we upgraded.
If your husband is handy, installing solar panels is not such a huge thing. We installed panels on two different trailers and on a sailboat -- in each case we did the installation without shore power and without a generator either.
We've written a lot about our solar panel installations on our website, including an easy-to-digest solar power tutorial that explains the various components used in a solar installation:
RV Solar Panel installation and Solar Power Tutorial