M/Hing without EHU..

Completely agree with this.  There seems always to be a tendency to over complicate things, by claiming that you need to buy lots of extra kit. I don't believe this is true. It would be interesting to know what size solar panel the OP has as long as it is not Mickey Mouse sized 20w it should cope in my humble opinion.

 But that's the point it's just an opinion, which is why I would suggest seriously to the OP next time you go away, don't plug in that way you get some real data about what you use and what you need.   This gives you the opportunity if it all goes horribly wrong (and it won't ) you can plug straight back in. It might cost you £5 extra for the gas you use, but a cheap price to pay for what you will learn. 

i agree, for an 8 day holiday with driving in between, its not worth it.

however, as they are dipping their toe into Europe in September, this may become longer tours overseas and then there might be a desire to stay longer on sites yet eschew the offer of expensive ehu on some countries and (possibly) use local gas to supplement battery power, which in turn might be added to with a solar panel.

on our first long term trip in Spain, all the 'locals' (brits) used solar for lighting, charging phones etc, but local gas (cheap and available) for hot water, heating etc as it was far cheaper than the metered leccy.

to use the gas, a Jumbo adaptor was required, so once there is a desire to stay longer, perhaps some of the above ideas might take on more relevance.

The OP asked a question about relatively short trip without ehu in late summer.  Basically they want to dip their tow into the water of, off grid.  To respond to this sort of question with you will need to buy a safefill bottle and extra batteries.  I just don't think is particularly encouraging or helpful.  I am not anti safefill or extra battery, I have both but one step at a time.