The 78-80 attack shouldn't take long at OSRS GP all, maybe a couple days, possibly an entire week if your progress is slow. Personally, I'd recommend training with Green Drags, or Blue Drags in Taverly Dungeon if you uncomfortable with the wild. It's an extremely slow experience. however, it's good cashwise.
If you're looking to get speed, exp. and speed, I'd look at Yaks, Experiments, Flesh Crawlers (SHoS) and possibly Rock Crabs. Each of these areas will have a decent flow of exp. In addition, they are being relatively casual and low risk.
For Summoning It all depends whether you've got the charms. If you're lucky enough to have them and you have them, it'll take just a few hours or perhaps less. If you don't, no one knows what time it will take to gather them. I'll go with the assumption you have the charms.
From 22 to 31 make Granite Crab pouches. This is fairly effiecient in addition to costing very little charms. You'll need about 1,300 empty pouches, gold charms iron ore, and some 10,000 ounces or so of spirit shards. This is likely to cost you somewhere between the middle and high 200k.
Between 31 and 40 you'll make Vampire Bats. They are a decent source of buy RS gold exp and their ingredients aren't as difficult than other. Collect 170 blank pouches bloody charms and vampire dust. They also have 13,400 spirit shards. It's going to cost you around the mid 300kish.
