I posted a reply to your intro which basically just notes what you should be expecting to have seen with 'health clearances' -- this is really critical. If the breeder has them as noted, then you are very fortunate to have found someone with available puppies so quickly and it will be wonderful to get your new girl home!
Just be very, very careful and very sure -- there are a lot of duplicitous breeders out there, especially those focusing primarily or solely on the pet market, and they can be very deceptive with people who don't know what *exactly* they should be seeing in terms of health clearances (eg cardiologist, NEVER only vet heart certs (generally meaningless), from within a year of the breeding, cardio clearances for all four grandparents at age 5 as well; at least one of the parents should have a grade A on an MRI cert and both parents should be scanned if at all possible (I would not take a puppy myself otherwise); ophthomologist clearances on eyes, and hip scores. I'd want to know the dog had good patellas as well. Both parents should be at LEAST 2.5 years old, both with parents at LEAST age 5. (those are the most basic requirements of the MVD protocol ). You want to see the physical pieces of paper. www.roycroftcavaliers.com has images of what certs look like as does www.cavaliercampaign.com.
It is actually a bit unusual for a breeder to have both parents -- most would tend to only have the mother, and will then expand their gene pool and bring in a stud dog from outside. There are of course exceptions -- but having both parents can often be a sign of a breeder who is turning out litters for the pet market, with no proper testing and mediocre breeding stock to start with. So given that this person has both parents, you would want to be especially meticulous on making sure the health clearances are meaningful and actually exist (eg you can see them and know what you should be looking for). If not -- I'd back out of the arrangement and I can give you the name of a very good east coast breeder contact who no doubt can steer you in the best direction.
There are some good questions to ask any breeder (and what to expect in reply) HERE.