The stated lead time is 120 days out. I'd check periodically before then. On an Alaska cruise this June, we were able to book more than 120 days out...but that may have been due to growing pains on the new web site. There have been reports about this on other cruises and sometimes specific tours were full by the official start date...that's why I'd check at intervals earlier. You can book as many free (or surcharged) excurisons as you wish as long as they don't overlap...I think the requirement is a 1 hour gap. This seemed to work as advertised for our cruise except in one case where there was a 75 minute gap and the web site wouldn't accept both. I booked the one we cared most about on the web site and then called Regent and had no problem getting them to add the other.