Gate 10 looks like the easy, low-stress option.  Do those spaces sell out quickly like hotels? Or can I just relax and click the button in May?

When using Gate 10, get it on day 1 of event registration and make it a priority item and you're likely fine. 

Event lists are processed in order, items by priority. Once your list is up, you should be fine.

Last year, I was able to get a 4 day pass several weeks after event registration started.

How much does the gate 10 parking cost?  I didnt use this last year so I paid quite a bit for parking garages or parked and walked 3/4 mi away

It was $62 for 4 days.  The lots are not that close to the ICC (1/4mi-1mi away), but they have a shuttle.

Gate 10 was such a nice option for parking, I would say you could wait a bit, but not too long to get an event ticket for it (they did sell out last year but not on day 1).

Will agree that the lots are not that close, but not too far of a walk if you want to hoof it. 
The shuttles are frequent so if you need to wait it wont be long (we never waited more than 5 min for a shuttle)
They have multiple lots so that can get slightly confusing on the first day but after that its a breeze.

Does the Gate 10 option include in and out privileges? Meaning if I wanted to meet friends that live in the area at dinner I could drive back to the parking area and get back in?

​​​​​​​_____________________________________
Alec Usticke, Fans of Gen Con Facebook Group

I have used Gate 10 a couple of years.  I found it be fast and easy.  But I parked my car and didn't return until the end when I was ready to drive home.

None the less, I feel it is a good option for everyone.

I use the parking garages near the convention center because I like to be able to return often to my car to rest for a moment or drop off purchases and/or gaming supplies. Plus I like to check on my vehicle and they have cameras and it is covered. For a few extra dollars it is worth it to me.

I've used Gate 10 for the past few years, and it's worked out fine.  I wait until our group has accumulated 50+ lbs of purchases, then get a Lyft to take me to my car & stash all the swag.  Round trip was about $8 before tip.

Parking at Hotels is around $45 per day. Gate Ten offers shuttles to the hotels so this is your best option.

Also, don't forget to be nice and give them a few dollars.

Do the shuttles run to the hotels on tuesday?

You'd have to check with your specific hotel to see if they provide any kind of shuttle.

The shuttles went to the downtown hotels. They just didn't go between hotels and the ICC, unless you wanted to change shuttles at your parking lot which would be a long detour.