Tips/Help with my outdoor guerrilla soil mix please!

I'm getting ready for my first outdoor grow this summer, guerrilla style. I'm totally overwhelmed with all the soil mixes I read on here, not knowing what is best for my conditions. So I thought I'd see what you guys have to say about it.

I'm going to be growing in the Cariboo region of BC, near my cabin, 5hrs from my home. The weather can go either way up there, but generally it's pretty dry during the summer, with intense thunderstorm downpours(and hail) some days. But there have also been years when it's been cold and wet the whole time. Hard to say what this summer will be like.

But seeing as it's 5hrs away(and I can't spend the whole summer up there), I need to be able to leave it for up to 2 weeks. I'll be watching the weather reports and asking other family members who might be up there what it's like.

So I think I should make my mix on the better water holding ability side vs good drainage?? Is it better to have over watered or under watered plants? Remember they need to be able to go up to 2 weeks before I can potentially tend to them.

My local dump gives away a free cubic metre of compost every May, and I can get Promix BX from a Hydro shop, as well as a good selection of top soils and potting soils from my local nursery(both organic and some with synthetic nutes added). Any other amendments like guano and meals I can order online. Will I also need lime?

My strain is going to be Texada Timewarp, which is 70/30% Sativa/Indica. I think they a light feeders, according to what I'm seeing with the moms in my hydro setup.

So given my situation, what is a good recipe I should be going with? Or any general tips you can give me?

Thanks a bunch

If you can get ProMix, just use that. It's the best. Then get any Veg and Flower nutes you may want, you'll likely only have to apply topdressings. I like guanos, myself, and have also had good results with blood and bone meal. I like organics and would never advise the use of anything but. You'll likely want a good bit of perlite if you wont be able to visit often, and then camouflage the perlite with mulch, then native leaves and such. 2 weeks is a long shot though. I say it often, but on hot summer days when it hasn't rained, I have to give each plant a gallon a day. I assume BC doesn't get as hot as the states, but I'm unsure. I doubt you'll need lime at all, unless your native soil is Very high or low pH. Good luck man