Parking at the hotel is included with all hotel shops so I would NOT include that as an expense. They pay milage at the standard federal rate, though, so you can bid for that. You get a feel for what's allowed with travel expenses over time. Some hotels only pay up to $75. Others are ok with $500 for the right evaluator.
You will not see the full requirements until you receive the assignment. You also get a feel for requirements over time from the postings.
For me, a dinner takes 1-1.5 hours to write up. The easiest hotel takes 8 hours, so that might be potentially double for you first time out. I generally leave myself a full day after my return from a hotel to write the report.
I checked out of one of the easier hotels yesterday. I wrote for about 5 hours when I was there, but also took an added dinner assignment in the area since I had one open meal. I wrote for another 3 hours on the trip home yesterday and still have probably 3 hours of work today to be completely finished. I also got 3 days away from home, all meal and my flights totally covered, so it's worth 8-12 hours for me.
I work fastest and best when working from home, because of my comfortable home office set up. 8 hours of work from my home office = 10-12 hours in an airport lounge, hotel room or on a flight. It's just not as productive with smaller screens and laptop keyboards.