Need Help! Have Big Collection Of Early Stamps

You have two long established stamp buyers/sellers in your immediate area who you could probably get a face-to-face read out on the estimated value of this collection. I would always find that preferable to mailing off unknown value items to an unknown entity. I'm not vouching for either (Dr. Bob Friedman in Woodridge, Rasdale Stamps in Westmont), just saying I would find it preferable.

Definitely would like to see a clearer scan of the first stamp -- that 10c Washington actually looks more like either the reprint of 1875 (Scott #4), or a fake of same. I don't think it's #2.

NobleSpirit sells mountains of collections on ebay on consignment. They have a good chance of getting higher realizations for lower-end material than Bob Friedman or Rasdale would (they have tons of followers on ebay), but they'll also take a healthy chunk of the sale price for themselves. I'd get a better idea of what you have before committing to either: if you do have better material in your collection, NobleSpirit might not be the right choice.

I'd be willing to bet there's no high-end stuff in the collection unless Grandpa got lucky somehow really lucky because you never was able to spend much money on stamps he actually never had much money just a lot of stamps

Wow, you have some great stamps in this collection. I agree it would be nice to get some of the more expensive stamps certified, although I know this costs some money, but worth it. I also agree that joining a club, going to a show, or visiting a dealer in person would be helpful. But most important, do not rush and don't be pressured into anything.
I know Mystic Stamp Company offers a basic stamp ID service cheap ($3) for looking at a scan of the stamp you are interested in assessing. Perhaps you can try that first to see if you are in the ballpark. Then you can decide from there. At least you will know if you have a genuine stamp or a copy.

Mystic's service is not intended to be used as an expertizing service (i.e. determining whether the stamp is genuine or not), just as an aid to identification. Also, they don't guarantee any particular degree of accuracy -- which is good, as some details, like watermark or paper type, can be difficult or impossible to determine just from a photo. You can often get a free opinion, just as good, at a local stamp club, stamp show, or stamp dealer. (Or by posting more scans here.)