As only a suggestion, if you want to make the most of your Alaska trip, you might want to consider heading to Seward your day of arrival- not knowing the time, but if in the afternoon, very doable. This would free you up for some Seward touring, if of interest?
Anchorage is a "city", and may not offer the most for your short time.
For Denali park, sorry, I NEVER would recomend a stay at the McKinley lodge with having Denali park activities. It is 100 miles aways, so way more than the "hour" mentioned between the two.
I stay frequently at the Denali Park Hotel. Reasonable prices, fridge and microwave in rooms. Clean basic. Plenty of other options. I would not consider the Princess property, nothing special and congested.
For your Denali park visit, in your timeframe, purchase the Eielson shuttle bus. You have the wrong idea with your "tour company" reference? If for Denali Park? I don't recommend the tour buses, and only one company- Aramark for independent visitors. You are too early for Kantishna, I believe?
I suggest you consider taking the train to Whittier, or an early bus, and getting yourself on a Prince William Sound boat tour, just a great option.
There are many car rental options. Enterprise, is noted for good rates. There is Dollar, Payless, Thrify, Alamo plus all the other majors. Independents as well. listings www.anchorage.net