@Dr. Tiki - Welcome to RCC
If looking for advice, I might steer clear of the scx24... It's a fun little rig for what it is but unless you HAVE to keep it small... limited funds, limited space, primarily indoors, etc... I think you'll be happier with a 1:18 or 1:10 size rig.
I like my scx24... again, for what it is. And yeah... lots of aftermarket parts out there. But at least for me and for some others, the limitations sort of dampen the long-term thrill. Some people do find the opposite to be true and have plenty of enjoyment running the scx24 indoors/ outdoors but unless you're fairly sure that the small size is going to scratch your crawling itch for a long time to come, you may find it sitting idle on the shelf after a short honeymoon phase.
Also keep in mind that working on, modifying, and upgrading an scx24 can get old for some of us. The hardware is also insanely small and can be frustrating to hassle with. Of course your run-time is greatly reduced as well compared to a larger crawler so that may also be worth considering. One thing that's pretty cool with the 1:24 scale crawlers is the ability to make and modify your own indoor or outdoor course at home so that may be a factor in your decision.
Traxxas makes a very cool and capable TRX4M that is 1:18 scale and it has a ton of aftermarket and manufacturer support. It's a little large to run exclusively indoors but its size makes it a good choice on a budget and on all kinds of terrain outdoors. Like the scx24 it's small enough that you can toss it in a backpack and go. But of course your run time will be longer than with a 1:24 crawler and you'll have more choices where to use it. Redcat also has a 1:18 crawler called the Ascent which a lot of folks seem to be pretty happy with... Maybe worth looking into as well.
Obviously with a 1:10 the choices are limitless in terms of basically everything... upgrades, body types, support, etc, etc. Traxxas, Associated, Vanquish, and Axial are leading the pack with their offerings in this size category. I've been extremely satisfied with almost everything about my Traxxas TRX4 rigs from the standpoint of quality of components, performance, aftermarket and manufacturer support, and wrench-ability. They are fun rigs right out of the box and much more so after adding personal touches and modifications.
You touched on how and where you want to use your rig and that's an important part of the equation. A larger rig is more ideal in a setting where you want a long run time and maybe want to get some exercise in the process or if you have an endless amount of rocky areas to explore... and they're great if you have lots of trails/ wooded areas and enjoy getting outdoors for a few hours at a time. But if you just have some smaller rock-piles or outcroppings close to home and don't have a lot of time to run an R/C rig than you may be just as content with a 1:24 scale. From what you mentioned though, I think you may have a hard time covering all your bases with a "one size fits all" crawler and I feel like you might be happier with a 1:18 as opposed to a 1:24... imho.
Fortunately, this forum has all kinds of people running all kinds of rigs so you should find any questions that you might have, appropriately and honestly answered. Good luck on your search... oh and btw, as a guy currently resurrecting an old RC10GT, gotta say I love the old days of nitro!
