I went to Cuba last year, and it was amazing!!
It wasn`t a walking holiday as such but we did a fair amount of it. As said above, if you`re going to go, the sooner the better, if you want to experience ` todays` Cuba. I don`t think it will be too long before the country is overrun with Mcdonalds and Burger Kings!!
The one walk we did was to a place called Vinales, where the tobacco plantations are. It was a memorable day but very very hot. I don`t think I`d have liked to walk too far in that heat. I was there in May, so it might be worth keeping in mind how hot it can get there during the summer months.
In a nutshell....Cuba? I loved every minute of it ...you won`t be disappointed