Hello Dave.
Personally- I like the Forest service road better than the main access road. Honestly its probably not any easier. I'm not a hill climber per se so for me (210 to 213 lbs) its 50 to 105 minutes to cover the 6 miles (ave grade ~8 %?) from Govt Camp to Timberline.
What I like about the access road- low traffic and for most of the climb you are in the trees. Another aspect- there are sections of the main access road that can be demoralizing. Just when you think you are at the top- you look up to see the "guard rail" continue ...way up above you. :. >
This year however- make sure you check in with the Forest Service. I would not be surprised to find snow still covers the Forest service road. We had a great snow pack this year.
Last comment- be sure and pace yourself, eat well. You'll be climbing (smaller passes) on the return to Hood River too.
A funny perk- be prepared for folks visting Timberline lodge to look at you like you are the most *crazed fool* on earth. They are awe struck to see cyclists ride this route.