Crumpler only signed in 2010, so most of Vollmer's play at LT was without him. I think Watson was the one doing most of the blocking at TE in 2009. Still, offensive production certainly didn't suffer from Vollmer at LT, and it may have even improved. He's a more than adequate emergency replacement if Solder can't quite cut it immediately.
That being said, if training camp begins as planned, I think we'll see Solder as the starter at LT for the foreseeable future. Mankins and Light both started opening day, and they were picked a half-round or more later. Given that history, and the fact that this team has been notorious for not holding onto veterans too long, I find it hard to believe the team would want Light for as much as a single season, and I doubt he'd take anything less than a 2-3 year contract. This off season has admittedly been more truncated than most, but not as much as people think. Truly intelligent and hard-working players like Solder will be just fine with a full training camp.