Honestly, IMO, unless you have money to burn, your 4 year old does not need a TREK. First off, a bike for a 4 year old is VERY small. She will outgrow it in a year or two at the most. This is a bike that is going to get banged around and dropped a lot while she is learning to get the hang of it.
My son learned to ride on a nice little used bike we got from a bike repair shop. he outgrew it, moved up to a bike from Target, and now at almost 10 has a very nice, much more expensive Mongoose Trail bike from Dick's Sporting Goods.
He is old enough and a proficient enough rider now to really USE the bike, and also to appreciate how much it cost, and take care of it, lock it up, etc.
You and your hubby may be avid cyclers, and that is great. But it will be quite a while before your 4 year old is keeping up with you on the trail all on her own! Just because you CAN get her a TREK doesn't mean she needs one. Get something less expensive, save the money and get her a really good bike when she can use and appreciate it.