I grew up on the Oregon coast (Newport), went to school at OSU (Corvallis) and have lived in Clark County, WA since 1989. So I am pretty familiar with the areas you mentioned. All are very suitable for permaculture endeavors. Although Battle Ground is having some strange politics lately, so maybe keep that in mind.
This organic farm in Philomath is for sale. But jumping directly into full-time farming is quite a leap.
https://www.gatheringtogetherfarm.com/about-gtf
You didn't say if you plan to have a "day job in the city", "work remotely" or try to make a living from the land? i.e. what sort of commute do you anticipate, if any? If you plan to have a day job, how big does the town/city need to be in order for you to find employment there?
And perhaps more importantly, what do you wish you had known before buying?
I’d especially love to hear about things that aren’t obvious from real-estate listings: soil and drainage, wells and groundwater, winter saturation, septic issues, county permitting, wildfire/smoke, microclimates, growing seasons, taxes, insurance, invasive plants, access to supplies and anything else that surprised you after living on the land.
We are on a relatively large lot in town (0.7 acre). I do permaculture mostly for fun and to be able to harvest year-round. I share my excess with a local organic farmer who visits occasionally to harvest my excess. And of course I share with family, friends and neighbors. We are on city water, although I use very little of it, mainly for my native plant "nursery" and vegetable hugel bed.
Re: before buying, I wish I would have more closely examined the soil across the whole lot. Until our house construction started, I didn't realize that over half the lot is covered in clay from when they built the street. In your case, I would also drive around the neighborhood to see what the neighbors are like, and imagine if you could get along with them. e.g. if the next door or upslope neighbor bathes their property in chemicals, you may have some conflicts.
Re: wildfire/smoke, those are everywhere most summers. Worse the farther you are from civilization.
Re: invasive plants, I highly recommend that you learn to identify them when they are small. Much easier to deal with at that point vs. when they are bigger. We have some nasty ones e.g. himalayan blackberry, canada thistle, etc. Spend some time here:
https://www.nwcb.wa.gov/printable-noxious-weed-list But, those of us who have lived here a while have learned how to tackle them, to the point that they are now just a minor annoyance. I do however get frustrated with new invasive
insects, which I have to learn and battle. e.g. apple maggot, Spotted wing drosophila (SWD), marmorated stink bugs, etc. I use "fruit sox" on my most important fruit, which works well but is labor intensive. I have tried to incorporate a lot of native plants & wildlife habitat into my food forest, which attracts a LOT of birds and parasitic wasps, who eat a lot of the insect pests. But not all of them.
I'm happy to answer any specific questions.