My take: Hold off on the K1. Buy a used K-30 or something that was an entry level but still weather sealed body if you can find one for about $100. Or if you want a little more room to grow, get a used K-5 or K-7. They're all excellent cameras still. Main difference is going to be that the entry level body has fewer controls, so if you need to do some things, you end up going into the menu, or holding down multiple buttons.
Once you decide you love it and you find you're actually USING it, then feel free to pull the trigger on the top of the line body you want.
I say this, because if you look at camera bodies for sale, when people post how many photos they've taken with them, a lot of times you'll see the high end bodies, several years old, with only a few photos taken (the photo file's metadata tells you how many photos have been taken on that camera).
If it's stretching your budget, and you're not already an avid photographer... just get a nice used body. Once you hit a few thousand photos, that might make the investment worthwhile... but even moreso, it's after hitting those, when you say to yourself "I really wish I could do this specific thing but this camera does not support it and the K-1 does" - Then you can sell the used body for probably $25 less than you paid for it and buy the shiny new thing, which might have come down in price by that point (used gear is the best IMO. There's a sizeable price drop from new to used, but not much of one from used to slightly more used, so you don't lose much if you start with a used product and resell it later). And take a few hundred dollars you were going to spend on the body and get some nice lenses. Used, of course.
A da* 50-135 and DA 20-40 limited lens pairing give you excellent quality with weather resistance to go along with the body, and cover reasonably wide and reasonably long, so you won't be hurting much for typical photo needs. The different sensors between the bodies aren't that terribly different from one another.. a bit more noise, a bit more megapixels, maybe less capability for photos in very dark areas... the photo's going to come out looking roughly the same, all the pentax cameras from the K-20 on (when they switched from a CCD to a CMOS sensor) are going to have pretty close to the same color rendering and so on. But mediocre glass isn't going to make you love photography, even if its on the best body, while good glass is going to look every bit as good on the older bodies as it does on the newer ones. And good lenses retain their value better than bodies do, in case you decide to drop the hobby - you can almost look at buying any good lens (used especially) as a cheap long-term rental with a large security deposit, and an option to keep it.
Or, you could just buy a shiny new K, play with it for a couple weeks, get frustrated with all the functions, and then quite possibly end up letting it sit in a bag for months on end and only take it out for birthdays and other random stuff, then finally sell it with 200 actuations at a substantial loss in a couple years. Not saying that you would - but it does happen a lot.