Here are a few suggestions. The books may (will?) have incorrect information about:
1) Cage sizes. See the Main tab of this site for the recommendations. The ASPCA agrees with these, and many GP sites and vets link to it.
2) The role of vitamin C. Scurvy is not nearly as prevalent as the vet textbooks make it out to be, partly because so many more GP owners feed fresh veggies than they used to.
3) The need for a guinea pig friend. They're not solo animals, and they do much better with a buddy.
4) The competence of small animal (read "dog and cat") vets to care for them. They aren't even similar to either one, and regular vets get little to no education/training in the care of exotics. Some do actual harm to them, and we never recommend that someone take their pig to a dog-and-cat vet except possibly for eye emergencies. Eyes are pretty much eyes are pretty much eyes, so the vets can't do much harm there as long as they don't attempt surgery.
5) Guinea pig weights and diets. The recommendations in vet books are made from observations of lab animals, many of which are sacrificed or given to rescues at a fairly young age, not family pets. They are normally heavier than the vet books recommend/observe, and their diets need to be much more varied.
Guinea Lynx is another excellent site, with many medical references, and many vets and rescues also link to that site.
Good luck!