So a group of friends and I attended 2 of the last 3 gencons, missing 2019 and our trips were booked at outlying hotels using expedia and we rented a car to commute to the convention.  We never really tried for the lottery and our trip for 3 people including flight, car and hotel was around 750 per person.  This worked fairly well, but we may be bringing a bigger group and a child, so a connected hotel would work much better.

So my question is, from anyone who has gotten connected hotels via the lottery, what were the costs per night per room? We are trying to see if we want to just book our trip again on expedia or wait and try for the lottery, then just book plane tickets.  But for some of our group, cost is an issue so we are trying to compare.

Thanks in advance for any help! See you guys in 2020!

Roughly $250 per night. 
The rooms are smaller than at outlying hotels, so don't try to cram too many people in.

After taxes 4 nights at the Hyatt Regency is just under $1200.

The full list of prices for 2019:  https://www.gencon.com/attend/hotelmap.  I think you add around 17% for taxes.  And of course parking is additional too.

remember to factor in the price of parking

If you do not want to wait for the room block, you can also try to get a room now--it will definitely be more expensive than getting an in-block room, but if it makes your travel plans more workable, it might be worth it.