Where have people stayed when doing this event? Not really interested in hotels/motels/inns and the like. We would prefer to rent a house on the lake. There are some options I saw on VRBO or through Geneva’s visitor’s center/chamber of commerce. Unfortunately not very cheap during the peak summer period though.
Anyone have any recommendations?
im local. The luxury of a lakehouse will come at a premium as our season here is short. If you have fam traveling with you and make a 4+ day trip of it will be worth the $. Local vineyards, hiking, waterfalls and an incredible beautiful clean lake (s). You’ll enjoy the race regardless, awesome course and organization that is unmatched.
I grew up nearby in Liverpool (‘burb of Syracuse) so I’m pretty familiar with the area as a whole but I have never needed lodging in the area since I normally just crash at my parents’ house. I did plan on staying for 4-5 days and then heading to Liverpool to visit my parents for a couple of days. My wife and son will be with me. My brother may come in from Boston to do the race so that adds another person or two if he brings his significant other. Part of me would hate to spend $2000 to stay for the week when a free place is just an hour drive. Granted, Liverpool doesn’t offer the same scenery and serenity that a nice lake house on the Finger Lakes would offer. 
Considered B&B’s?
Not really. B&B’s creep me out. I don’t want to stay in someone’s house while they’re still there. I don’t want to interact with them and I don’t want to be on pins and needles all the time. I want to be able to fart and walk around in my underwear if I want. 
You could also try Canandagia Lake for a rental. The drive from Canandagia to Geneva would be about 20-25 minutes. Although, the prices on Canandagia might not be much better.
Another place worth considering is the Glenora Winery or Esperanza Mansion in nearby Penn Yan. The Glenora winery would certainly be cheaper than staying on the lake, and it does have a lake view (albeit several miles away).
It’s at least worth considering if you don’t want to spend $2000 per week for a lake house.
I’ll check those out.
Edit - I stayed at the Esperanza Mansion a couple of years ago for a wedding. Nice place.
I did this race in '09 and we stayed on the lake renting a 3BR 1Ba on the south west side of the lake via VRBO. It was beautiful but not cheap. As I recall, it was about $1200 for the week. About 20min drive to the park/race venue on Sunday morning but no traffic at that time of day.
You could also try a cabin on Cayuga Lake in Seneca Falls, likely cheaper and a 15 minute drive to the race.