And I don't mean just look. Try a demo, grab a promo, maybe buy a game.

I have like ten events scheduled and I'm trying to plan ahead. 

The entire convention...really to get to EVERY vendor and play any demos...that will take the balance of your time for sure.

For sure, I am not sure of the number of vendors, but you will busy from 10:00 to 6:00 every day with just your quest. Does that include all of the artists and authors, too?

I think in a couple of hours you could navigate the whole place and just skip over things you are obviously not interested in viewing, but there are a lot of booths!

Also, on Thursday it will be so packed with people and lots of lines will be long, like Paizo, Fantasy Flight, etc.

As for Demos, see if you can sign up and come back at a scheduled time so you do not waste time in a line just to demo a product.

Good luck!

Every vendor?  Don’t be ridiculous.  There are over 500 vendors.  Let’s say that 50 might contain things you want to actually try.  The hall is open for a total of 30 hours, which would give you 36 minutes at each one, not counting travel time, bio breaks, or eating.  30 minutes is not enough time to do much; many of the more popular demos have wait times longer than that, and lines to buy merchandise that can be that long as well.

If you actually tried to go to every booth, that’s about 3 minutes at each.  You can not even come close to seeing all the vendors. Focus on the maybe dozen that really interest you, and then spend time wandering around and  discovering new things. If you even try a fraction of what you’re suggesting, you’ll burn yourself out by Friday, and will have a very  crappy con experience.

500 Vendors
Vendor Hall open 30 hours (10am to 6 pm for Thurs to Saturday and 10 to 4pm on Sunday)
1800 minutes in 30 hours 

You maybe able to visit them all but not much more than that.

I always say do the vendor hall in slots of 2 to 3 hours each.  In the first and second slots visit the booths you have interest in, the other slots are just checking stuff out.  Total number of slots is your choice but I find 4 is all I need.    
 

It would take at least two days with minimum interaction.  With actual time spent demo and buying all of Thursday Friday Saturday 

As an example. We try to take our time and look at as many vendors as we can. We always seem to miss some because of the odd layout of some of the aisles, but usually see most. We plan little to no events between 10-6 each day. This year we have one event over the 4 days during the exhibit hall hours.

I'll underscore what others have said.  It's really big.  I walk the whole thing systematically and 'look' at every booth.  But, you can walk past a lot.  Attempting to interact with every booth doesn't seem like a good use of your limited convention time.  You should just skip quickly past the things that don't appeal to you.  I mean, are you really going to demo a pro-wrestling card game if you aren't into pro-wrestling, just because you are trying to do every booth?

But yeah apparently I underestimated the size of GenCon. 

"But yeah apparently I underestimated the size of GenCon. "

Ya think?

To add some context the first photo is of the crowd waiting for the show room doors to open on Thursday morning. The second one is from Mayfair's demo/play area on the show floor quite a few years ago.

Always found the ones looking down on the dealer room from the "secret' room to show more of the size 

Nevertheless, yeah, it is huge.  I often break up the thing into two parts.  Like walk half of it one day for two hours and then come back the next day and do the rest.  And that is just looking at stuff while trying to skip past stuff that doesn't appeal.  The place is so big that some dice booths have 3 separate booths throughout the convention.  I do think that if this is your first time, you should plan to spend a lot of time at the exhibit hall.  Especially if your alternative is playing a board game that you could play at home.  On the other hand, there are so many other things to do at the Convention -- costume show, True Dungeon, Escape Room, seminars, etc.  And I didn't even mention games.

ALL of the hours, and you still will not have enough time to visit and transact at every booth. Depending on the time/day, you can walk the hall at look at every booth in a few hours if you do not stop to play, buy, or really browse anything.