Supercharged Morganite is really good and somewhat abundant. At least, more so than Diamond. Onyx is more abundant than Morganite and a good starter material. If you can get lucky enough to get Mending III or IV, or to find a dungeon with mossy cobblestone and make the enchantment yourself, you won't need another tool for a long time.
Horses are still good for travel if you get lucky with a saddle. Seeing as there is new worldgen for dungeon lootables, you may be able to get one early game. Listen for the crackly energetic sounds underground for a guaranteed 4 chest "dungeon". I think they're from Chromaticraft? Or EssentialCraft.
For backpacks- you've got options. Here's what I recommend:
First backpack to iron: Use it as a general purpose bag. I keep it on me at all times to hold spare things, especially alternate tools that I don't need out all the time.
Second backpack to iron/gold: Add a filter (for autopickup) and a crafting upgrade. Put things like redstone, lapis, cobblestone on the crafting upgrade and/or the filter. Your backpack will fill up a lot less quickly. Put compressed/double compressed cobble in the crafting upgrade as well and you'll never fill up on cobblestone.
Third backpack to leather/iron: I haven't done this yet, but it wouldn't hurt to have a backpack solely for picking up those "few and far between" ores like tungsten, nickle, boron, etc that just fill up your bag with 1 or 2 each.
Get some tools with Area Miner on them and you'll save a lot of time on clearing out space. I cleared out this entire space with an Area Miner shovel/pick.
Thanks, and good luck. Make sure you set all your redstone channels and item channels right the first time, it's very annoying to troubleshoot once you get everything in place.
