I would not want to rely on solar unless you are able to keep the snow from covering the solar panels. I don't have solar panels but if I did I would have to go our frequently and clean them off. I have to snow blow my driveway every couple of days so I would have to clean off the panels at the same frequency.
i prefer to leave my TT in its nice cozy carport plugged into shore power. I replaced my WFCO with a Progressive Industries converter two weeks after I bought the TT because the WFCO would not change output, it was always at 13.6.