Its for a northern garter snake, Thamnophis sirtalis

This is the tank as is, note I just got it and haven't had the opportunity to clean it yet.

My plan so far is as follows.

1. clean and sanitize the tank
2. establish a drainage layer composed of low weight approximations of gravel, (several varieties seem to exist and I'll probably go with the most economically viable one)
3. put somekind of mesh in as a divider.
4. use a mix of potting soil, peat-moss, used coffee grounds, and possibly something else for drainage/ph balance as soil.
5. use the remainder of the aspen chip reptile sub-strait I have as ground cover
6. plant things, (this is one of the key areas where I would like help)
7. possibly include somekind of water feature, most likely a pond, possibly with a filter but most likely not a waterfall as I don't want the enclosure to be too humid which seems to be a risk with reptiles. (really want input on this)
8. introduce temperate woodlice, springtails, and common earth worms, (I'm tempted to get the woodlice and worms from my garden as I see both frequently but I recognize the threat of parasites, I wonder if quarantining them in sterile substrait for a few weeks would be sufficient to get any problem elements out of their systems)
9, create hiding spots for the snake and introduce some decomposible organic matter for the bugs
10. let that grow and mature over the course of a month or two, then order the snake and introduce it into the enclosure.

I would like the vivarium to closely resemble the native environment of my region in Massachusetts, temperate woodland/grassland. It should be aesthetically pleasing but I am more concerned about smell, I live in a relatively small apartment so apart from maintaining an ecosystem low on anaerobic bacteria, I am also keenly interested in flowering plants that produce pleasant odors. Beyond that plants my future snake would like and that can be easily maintained are ideal.

The tank itself is in fairly good condition, and has a standard wire mesh reptile cover. I have a small heating pad and a desk lamp for which I anticipate buying a uv bulb for the plants and the snake. I also plan to keep the lid locked on, either by putting something heavy on it or actually buying a lock of somekind.

This is a year long project that I can't begin until next month at the earliest, I don't anticipate actually buying the snake for several months. Just to be clear, I have never done this before, and I have only been researching this for a few days. I am probably out of my depth and would welcome any degree of advice.