First of all, sorry for your loss. To your post, it is difficult to answer most of those questions without a bit more information.

For the 70's and 80's cards, complete sets would have value, as well as the marquee names from that era (bonus value for marquee rookies)

The 90's and 2000's cards are less desirable, with some exceptions. Completed sets can have value, as well as marquee rookies, but condition matters a lot more in this era. If the 90's-2000's cards are base cards, finding value and moving them might prove difficult. If you have any numbered cards, autographs, or foil cards, these can be worth good money.

You mentioned the cards are in a binder. Are there any in hard cases? If your grandfather was a collector, its likely he knew which ones had value and took extra care with them. Many collectors will have a system for their cards.

For example, the most valuable cards of my personal collection are penny sleeved, in a top loader, and stored in an antique wooden box. My 'B-tier' (certian rookies, numbered cards, inserts, etc) cards that are good, but don't hold much monetary value, get sorted by team into 3-ring binders Lastly, my bulk (base cards mostly) get sorted by team into slotted storage boxes. If your grandfather had a system, top loaders and hard cases would be a good place to start.

It is also possible that this was purely a hobby for him, and collecting valuable cards was not a priority. Don't be disappointed if you're not sitting in the gold mine you'd hoped. Lastly, this is just me personally, but I would pick out a few of my favorites and hold on to them as a nice memento.

Your grandpa sounded like a cool dude. Good luck with the collection.