As anyone who has travelled in Cuba knows, modern internet access (whether WiFi or 3/4G) is still not available. So either you need to do all your bookings of casa particulares from home, thereby losing flexibility, or you need to find another flexible way of making reservations while you are travelling. For this, I can recommend the web site of Raul Fuentes, www.cubaparticular.com. You can make you first booking on the web site before you leave home, and then Raul or his wife will call you in your first casa, and get you a reservation for your next stop when you know where you want to go. They will also arrange pick-up at the Viazul bus stops, enabling you to stay clear of some of the most annoying jiniteros (hustlers). And the casas they have on their site are generally very good value. We stayed for 3 weeks in Cuba, and using Raul's service, we didn't actually have to waste time queueing for the Internet access at the telepuntos to make forward reservations. So, using Raul's service will actually save you time and effort, unless of course you are a webaholic and love queuing at the telepunto.