I got a Type B Voucher for a free domestic roundtrip in W, V and Q class. I am considering using it for a friend's wedding (MKE-ABQ) in May, or a separate little trip to somewhere for myself such as vegas or somewhere in New England.

Questions:
1. How should I determine whether I should use this voucher for the wedding or my personal trip to obvious get the best value out of this ticket?
2. How can I search for seat availability for these classes? My guess is these fare classes are rather limited, and don't want to spend hours on the phone to find the dates.

Thanks!