Simplicity is good, but "canned kits" are usually terrible quality on the controller. This stuff isn't rocket science, make learning about it a project for your geekier troop members.
Excellent value for the battery bank, if maybe "too much" capacity:
2x Duracell golf cart 6V deep cycling from Sam's Club, 200+AH for less than $180.
Since you may rarely deplete them more than 10-20%, they should last for many years, as long as you get them back to full 100% SoC as quickly and frequently as possible, ideally every cycle. And rarely if ever draw them down below 50%.
To that end, learn to use a cheap hydrometer so you don't need to spend about $150 on a battery monitor. Another advantage of old-school flooded batteries.
Solar controller: Victron MPPT 75/15, under $100
This will dictate your panel specs, rated no more that 75 volts is important. So starting with one panel at less half that, rated say 30-35V, up to 8-9 amps, since going over the 15A controller spec is OK. This will allow you to test out total output either in series, or go parallel, maybe even up to four panels in total if usage grows over time.
If you find your usage justifies getting another panel, do get if at all possible another one of the same model.
For this reason, best IMO to find a local PV shop and ask them to suggest one, you'll also save a lot on shipping. Figure $1-1.50/watt, don't go too cheap here - let them make a bit of profit since you'll also be getting valuable advice from them, maybe installation help, and you saved a lot bypassing them on the other bits.
As you're getting familiar with operations over a few months, if you think you want the second panel, keep in touch with the shop to make sure it remains available, get them to let you know if it gets discontinued before too late.
