I'm from the other side of the state and always had lousy luck growing outdoors, but I never was able to grow where they got good soil or full sunlight all day. A buddy in Ohio had one 10 ft tall, so it can be done.
I'd make sure that the plant was already well started indoors, as the growing season around here is fairly short for a plant like cannabis. I'd recommend an Indica or Indica dominant plant as they are better suited for our growing season. Sativas can be done but often start to flower later than Indicas and also flower longer. I sometimes went into November before getting bad enough frosts to force a stop... with Indicas, flowering started in August and lasted into October. I think you have good ideas about the soil... I would replace most of the native soil (it's mostly clay around here) and replace it with a good mix of potting soil, perlite, and maybe some composted manure and stuff. Make sure the hole isn't prone to water draining into it and standing as it's bad for roots.

I would also look for an Feminized Indica Autoflower type strain from seed.. I just bought some of this to add to my soil... Megacrop ..since my wife just told me soon as we can "Reno" here we come.. Sounds like my outdoor grow will be missing me alot :{

I live and grow in northern wisconsin with some of the harshest weathers around and there isnt much that I cant grow. If you are looking at seeds and go with reg photoperiod vs autos make sure that you stick to something that finishes under 10 weeks. You dont want long running sativas.
Might I also suggest adding composted manure to your soil (manure stays warm and helps keep the roots from getting cold)
Adding a silica suppliment is also important because it helps with EVERYTHING

Dont worry about frosts either... as long as it's not a hard frost they can go through several and be okay.
These I didnt harvest until november when most had taken theirs down in fear of frost and mold. My best plant did over 7 pounds dry.