Thanks
@smittytabb for tagging me. I'd have noticed the thread eventually but the tag got me here quicker. And you gave great advice.
@niehlin2 - Will you have a car? You won't need one if you want to stay within the central city, but for the parks and the gorge you certainly will.
As for food, the food trucks are indeed incredible and everywhere, and some of the best food in town can be found there. What happens for the best of them is they move from selling at a local farmer's market - the Saturday one at PSU was voted 2nd best in the nation recently! - to a food cart, to a full fledged restaurant. We have become quite a foodie town and I am sure you can get recs from many sources once you are here, for the cuisines you appreciate. Lots of NW/locavore places to choose from as well as ethnic food, especially all varieties of Asian.
Not sure if you'll be staying on points but if you have Kimpton points, the Kimpton on the Waterfront is lovely. The Three Degrees Restaurant there is fabulous in terms of food and view. And they treat Inner Circles beautifully. I've never seen any rooms but we get treated quite well whenever we go lunch or dinner.
I wouldn't waste time on the VooDoo donuts line - stop by and stay if it is short; otherwise just tell the folks in line you aren't buying and want to peek at the donuts. They are nothing special; it's the odd combos they come up with and mix of flavors that have made the store's reputation. Also the Asian food outside of Chinatown is far superior to the older places there.
It is was me, I'd stay downtown in SW Portland. One idea is to take the light rail from the airport for very cheap and rent a car in town to cover the days you will be exploring out of town or going to in town parks where a car is easier than using TRIMET (local transit). Then return the car, hop the light rail, and head back to the airport. It will save on parking fees and perhaps the rental as well.
I don't know of another location outside the city that would offer good food; not to say there aren't any, I just don't know. And most of the areas - Columbia River Gorge, Washington Park, Forest Park - you mentioned are all either in the city or within a close drive. Tourists visit them (as well as Mt Hood - there's a scenic gorge/Hood drive you can do) as a day trip from Portland all the time.
Hope that helps!