Can't drive. Won't fly. Won't camp. Where to go?

[IfYouCantSeeMyMirrors]

We're looking for a 2020 summer family holiday outside the UK, for a family including two teens. Camping and other uncomfortable accommodation is ruled out, as is any kind of expensive train travel (Eurostar). We need somewhere with good travel connections (to it and within it). In the past, when our budget was slightly higher, we did Amsterdam, the Belgian coast, Berlin, the Black Forest....Does anyone have any other good suggestions for what looks like being our last 'abroad' whole-family holiday?

Sorry, should say November/December depending on date of travel. Hardest dates to get bargains will be the Saturday at the start of the Paris February holidays when all the students travel home.

Channel Islands?

Mistigri that's what I thought, but averythinline posted about booking train tickets 8 months in advance. I wondered where she was able to do that, but it seems it's only for very specific sections of routes at very specific times. I want to book the whole journey at once rather than get stuck with one section unavailable/ extortionate. I prefer train travel, I'm sick to the back teeth of flying, but will probably just fly as train tickets are released late and seem to be more expensive unless you are very flexible with dates or lucky.

What is your budget crucially? We got a last minute cruise deal, there was (this August) deals as low as £500 a person out of Southampton, this includes everything but alcohol usually. You do need to wait until 6 weeks out for the best prices though