What Silv has said is all pretty excellent suggestions. When I was at your level I tried Experiments. From 60 to 70 and OSRS gold it took me three days. It was dull as there is nothing to gain except for experience however.
It's a bit odd because I'm not sure the things I've done between 70 and 90. I do know that I've done certain tasks, but I haven't performed tasks like bosses who were rangy and the Circus. And of course, Cannon. If you're not concerned spending a few dollars, you can Cannon Dagannoths as you also range them.
You could also Chin however I wouldn't recommend Chin until at least 80or more. If you are going to Yaks could be a good way to get experience. About 40k is the most you can get currently. However, that could be pushing the envelope a bit. There are plenty of bots out there. I've never tried Fire Giants though. I've seen a lot of people using it when I was given a job to do them , however. It must be fine.
Aviansies are a great investment and a decent way to earn money. However, I'm afraid of Yaks and are beginning to get a lot of bots. I hope that I helped. It's probably among my weaknesses in CB skills on the subject of training.
In about a month, I'll be able to for Frost Dragons (85 Dungeoneering). Within 3 months, I'll be able to do 100 Dungeoneering (6 chaotics). I was thinking of giving myself two years (maxing out, etc.) before joining an Nexing team with professional equipment, or perhaps on my own if it's possible, or I could give myself a year to get CLOSE, or, heck, maybe evenmax out by playing Frost Dragons and rs07 fire cape service then also be able to have an ely after about one year.