I would concur with much of the info above. Do your research on the resorts and unit sizes you are comfortable with. Don't assume it's OK simply because you/re going through
DVC. Personally the only resorts I'd accept trading DVC given the current system are the Starwood (Westin and possibly Sheraton if i's added), Marriott's and possibly Sunterra (formerly Embassy) and I might consider Kona Coast but given how easy it is to trade into and rent, I likely would not. You can request 2 years out and I'd do so for what you know will work. You can always expand your request later if you find that other resorts or times will fit your needs.
Remember that 2 BR units are tough so one either needs to lower their standards (take lessor resorts) or try to get two exchanges that match up at the same resort. This is the route i took the last time we went to HI. I got two 1 BR units at the embassy through an independent exchange company not using DVC points.