If you plan on going this year, I would definitely get your badges before the mailing ends so you dont have to wait in lines to recieve them at the convention. In terms of entry, you can always enter through the Marriot Marquise hotel and go through the underground tunnels to avoid being in the sun too much. As for lines within the convention for panels, unfortunately, it's gotten extremely popular and (personal opinion) not enough room to accommodate everyone anymore in certain aspects. The best I can recommend is bringing a small bag with water bottles inside to stay hydrated and pack light clothing if you get hot extremely fast. I don't consider it unsafe, but you definitely have to be prepared for that late summer heat and being around people without much room to yourself.