I'll be curious to see where you go. I know nothing about MTB riding in Europe. The better weather is likely to the south and I think parts of southern Italy are kind of remote. You might also do some research on hiking and find out where trails are and if they share them with bikes. Another neat idea might be to find some pilgrimage routes, although they now probably follow roads but not always. Finally, one option for shelter is staying at monasteries - my sister did that a bunch in Italy a few years ago and had a great time. Might be fun to do that for one night if it works into your schedule, location, etc.