I’ll try my best - I know nothing about the hotels, so just look for something that has decent reviews and prices, I guess?
The L is easier to understand and faster than the buses, but obviously doesn’t go quite as many places. If you have an iPhone, I recommend the Hopstop app for planning bus/L trips between places. Go to the CTA’s visitor’s guide to learn about the various routes, payment options, etc. They do not take cash/credit cards on the buses! Check into how to buy a fare card by reading that site, and of these card options, you want a transit card or magnetic stripe pass. Transit cards are thin and bendable, and can have more money loaded onto them at transit vending machines. Chicago Cards and Ventra Cards (hard plastic like credit cards) are more for residents/regular visitors.
Taxis - well, they can be pricey if you’re traveling several miles but they definitely have their use. They have to take credit cards these days, and many/most have automatic swipe machines mounted in the back. If you don’t have cash, poke your head in the cab and before getting in, tell the cabbie you don’t have cash and have to pay by card. It’s amazing how many cabbies claim their little machines don’t work if you wait until you’re underway (wanting to work under the table, I’m sure) when the machines seem so durable in stores! Fares are posted.
Pizza? I’d say Piece in Wicker Park, but that’s not “Chicago style.” (Not really fond of deep dish myself.) For that, try Pizzaria Due, or Lou Malnati’s, IMO.
Dogs? Hot Doug’s is pretty fantastic.
Don’t do the Sears Tower, IMO. For that you have to buy tickets, go through security, typically wait a long while to get up there, etc. Instead, go to the John Hancock Center off Michigan Avenue (“the Magnificent Mile”), take the free elevator up to the lounge level, then stay in the bar, buy a drink as a way to thank them for the lovely view, and enjoy the beautiful skyline. It’s gorgeous at night especially, as long as it’s not foggy.