Well, I am not sure about being able to "afford" a comprehensive solution! We will be wild camping to try and keep costs down, but staying online is probably higher on our list of 'needs' than some people might agree.
I have two dongles, at the moment, one is an Olivetti (part of a deal with TIM in Italy) and the other is ZTE (part of a deal with SFR in France) - I guess they are both locked...not sure how to test this in the UK. If necessary, I am happy to source another, unlocked dongle.
Budget estimate...not really given that too much thought because it will need to be balanced with usage. If it starts getting too expensive, we will have no alternative other than to go the hotspot route. What we will be able to afford is going to be dependent on other things too - fuel and food costs, breakdowns and so on.
How long...probably three months on this trip, but one of us may stay out there after that, maybe. Whichever, we will head out again in September for another three months up to Xmas. You have probably worked out that we are retired!!
Weirdest...I have no idea!! I will guess the area around Estonia, Latvia and Lithuania. We are planning to avoid Russia and Belarus...too much hassle with visas, particularly when don't have a strict itinerary in mind. Perhaps next or the year after, we will think about being more adventurous and visit places where the western culture has had less influence. I do travel alone sometimes, and I do have some concerns about being a woman travelling alone.
I missed out on doing gap year things 40 years ago and I want to make up for it now!!
Polly