Hi, It seems like I find myself saying this a lot on these forums. "this is my take, but wait for a more seasoned member to give better advice. I seem to be decent at self training, but its no substitute for experience, not to mention, I've incorporated many of the tips given here into it. First, id like to say, congrats on your first race/event! Way to just dive in there after 3 months!So 17 miles and roughly 3,280 ft of climbing! Sounds pretty steep. If it were me preparing for this:
-Focus on 1-2 hour rides,4-5 days a week. You should pretty much live in the hills until event day. No sense in doing rides that are too long, Id say no rides longer than 65 km(roughly 40 miles).
-Do what I like to call "power climbs". Thats what I use to refer to short, but very steep hills. I have a bunch of short hills near me that really help build up my lungs and muscular endurance. They range in 400-500 ft and are 1-3 miles long. I climb them as fast as I can.They also makes shallower climbs a breeze. Your even is short and steep, focus on doing short and steep climbs. Variety will keep you motivated, but if not, hill repeats will do.
-Know your gearing, if you don't have the proper gearing for an event like that, you may since your own ship. You may want to use a compact or mid compact chainring and at least 12-28 cassette to be safe.
- You've only been riding 3 months and may have not developed too many preferences yet. I'd say knowing your strength and weaknesses is a good start. If you tend to prefer being out of the saddle for climbs, work on being out of the saddle as much as possible during training. If your preference is to "spin", work on spinning faster for those climbs.
-When trying out the course, remember which roads were the toughest for you and try to ride roads similar leading to the event. When I just started riding, I was humbled by a hill that I couldn't even finish. I make sure to climb it now every chance I get and do so twice as fast as I use to. It is often more important to work on weaknesses than strengths.
-For a timed event/race, keep it light. Water bottles, flat repair, a bar or something to eat during the ride if need be. You may only need 1 bottle due to the distance, but don't worry if you need 2. You can always empty one later in the race if you're positive its just added weight(or just drink it).
I've never raced, so much of what I say is what id do to train for something like this. I'm sure another more experienced poster may give you better advice. Just have fun out there, don't put to much pressure on yourself about results. Sometimes a humbling experience can be more beneficial than a victory. I've been dropped a few times in fast group rides and seem to improve and learn the most that way.