With regard to Sally black, this is only useful if you have a high defence level or are using blitz/barrage to RuneScape Gold get around. Sally is a bit more consistent than slayer, and iirc it hits better at 70 mage than slayer dart does at 70 mage. If you're not blessed with 85+ def, or the magic level is 82+, you may want to utilize slayer.
The 78-80-80-80-80-80-80-80-80 very long, maybe two days, or a week if you slow. Personally, I would train using Green Drags, or Blue Drags in Taverly Dungeon if you uncomfortable with the wild. It's a slow process., but it is decent for cash.
If you are going for the most. and speed, I'd consider Yaks, Experiments, Flesh Crawlers (SHoS), or perhaps Rock Crabs. These areas are all likely to have a decent flow of exp., as well as being fairly casual and low risk.
For Summoning the process is based on how much charm you possess. If you have the charms, it will really take just an hour, perhaps less. If you don't, no one knows how long it will take you to acquire the charms. I will go under the assumption that you own the charms.
Between 22 and 31, make Granite Crab pouches. It's fairly efficient in addition to Buy Old School RS Gold costing tiny charms. It will require 1,300 or so blank pouches, gold charmsand iron ore, and 10.000ish spirit shreds. The cost is likely to be around mid- to high 200k.