What kind of road bike has a suspension fork?
If you are a decent rider and doing a fair amount of climbing which includes a lot of out the saddle, than bobbing is going to be a real problem...not only for control but as a power robber as you alluded.
On my 29er I have a Reba Race 100mm travel shock with a lock out that is just a fantastic fork. If I couldn't lock it out when needed it wouldn't be much fun however. If you plan on keeping the bike after the ride, you want a fork you can lock out if you must have a suspension fork.
Good Luck.