Which is best?

mrandredparis

I would like to train for a community race called "Ride don't hide" with my cousin who has agreed to form a team with me. I don't know yet how she plans to train but I have been looking at road bikes, I am going to follow a Cycling Weekly 3 month program. I have been volunteering for other mental health fundraisers as well but had really wanted to get physically involved. Yesterday I spoke with a sales person about some bikes that may suit me. He doesn't work on commission so he doesn't have any reason to sell me any one kind. The bikes he recommended were the (according to him the best bike for me)Trek Domane ALR 3, ($1500), and some other options Trek Domane 4 ($2000), Cannondale Synapse ($2000) and the CAAD 12 ($2500). Obviously, I would like to train for other races, not just this one. I really just need some help deciding what is the best ride for me as I really don't understand what is best. Some of the challenges that I am working with are that I have a bad back and early onset osteoporosis.
Presently I have a commuter hybrid mountain bike, big frame, and thin tires. I dusted it off just yesterday and rode over to the local bike shop. I would like to buy locally as it easier to commute(as I don't have a car) there for repairs, although the store is a franchise and the bike can be serviced anywhere their stores are while under warranty. Maybe you can all weigh in and give me your two cents. Greatly appreciated.

cooldad

How long is the ride?

I would look at something much cheaper initially and see if you enjoy it first.

mrandredparis

The race can be from 20 km to 100 km, I would like to train for 100 but am open to going lower if I don't feel I am up to it then.

mrandredparis

The cheapest bike this store has is the Norco Valence A for $750, is that a better price or less?