Dude I don’t know what your summers are like but over here in summer it’s like 96F most days for months on end, and all those lethal brown snakes all come out of their winter slumber looking for shit to bite at! It’s like a life and death thing here to get your shit together in the cooler months 
For decent soil you need air space in the root zone, the ability to hold moisture and therefore accessible nutrients, you need it to be friable so the roots can get through it, you need enough nutrients throughout the cycle and you need light and that’s about it. Coco peat is the pick of things, regardless of budget for guerrilla soil improvement in my experience.
So… I like guerrilla growing over all growing, there is just something about get way the heck out of anywhere and setting up a good patch. There are a few tools a tricks my bro and I have used over the years but when it comes to dirt we tend to look for somewhere near a creek, somewhere the soil is mostly silt and clay from flooding over the years. Soils like this tend to be high in nutrients, but can lack structure. Coco peat fixes this. In the cooler months we just cart out the 8kg bales of peat, unwrap them, throw them on the ground and leave them for a few week or till you get decent rain and they will expand and fluff up.
Then for nutrients, if absolute organic is your thing, those slow release pellets of manure, kelp,and guano are the go, if you are not such an organic purist, 6 month slow release granules and kelp for veg, add high phosphorus/potassium guano for flower. That is all I have used for years and have never had nutrient issues.
The other thing that is really useful is one of those augers you can get for a battery drill of ebay. Digging holes sucks, and these things are awesome. Also I take a small tarp for putting on the ground next to the hole, dig onto it, add the coco peat and nutes etc,shake it about and tip it back down the hole. This saves time and mess and mixes it all well.
And when it comes to carting water, a 20l backpack bladder is the go, get them cheap as camping showers off ebay. The ones I have used cost me $10 and have lasted 2 seasons.
we only have one venomous snake in our country and I’ve never seen one (Adder)
Well to give you an idea a 5 kg block of coco will do at least 5 good sized plants, give or take depending on what the soil is like. Over there it’s going to be decent I’m figuring compared to this baked part of the earth, so you could even make 5 kg stretch to 8 or even 10 plants. You can fit a 5 kg coco block in a mid size backpack without too much drama and you can saw it to make it fit. Per plant in the hole you woudl put 50g of 6 month slow release, and about the same of guano. If you are returning with any frequency then you can also use other things to feed it when you water. Honestly though, I rarely bother with adjunct feeds anymore because a decent nursery grade 6 month slow release alone with the guano tends to have everything the plant will need, especially for a shorter cycle like you are looking at.
