Most state have a provision in their law for residents of that state which will require you to register any llc formed in another state to register as a foreign llc. What this means is that if you fail to register in your home state, you lose the right to use the courts to settle disputes relating to the business in your state.
When you form an llc in another state, there are no such requirements except for taxes that may be paid on the sale of property in that other state. For this you need to seek the assistance of an escrow company or real estate attorney.
Your Oregon llc can own the property in PA but may have to file in PA as a foreign llc. Most of my clients who purchase property in MS where I work usually use MS secretary of state for their filing.
Some people to go NV or DE for their llc, you can create the llc anywhere but as mentioned you may have to set up a foreign llc in your home state.
FYI when working with attorneys, it's always good to do some homework first as you are doing otherwise you will be paying them to tell you what you can find in a forum like this. Bring all of the details to the lawyer, the more work you do, the less it will cost you. And by all means, see an attorney to get that level of comfort. The attorney can create the llc agreement for you, you can do the filing yourself on line.