I'll give you two cents for OSRS Buy Gold Construction. Oak Larders + Stealing Creation hammers. The speed of your flight will be at a time, you'll never think about what you did. Seriously. Building and dismantling them got me from 33-70 in a flash. it to be the Void Series of quests.
I believe that's the most economical way to go about it especially if plank-make all of your oak wood. I'm not aware of the minimum requirements in Plank Make, though.
For Agility, I suggest doing the Brimhaven arena + tickets until 55 in order to climb to the Wildy and earn approximately 500 xp per run. This doesn't sound like a lot , but if the user doesn't really pay attention to what you're doing, you'll find yourself climbing these last five levels quickly.
Smithing, I took The Artisan's Workshop - but the ingots downstairs. There's not much clicks, and the xp is pretty uniform. Farming, you just plant the most advanced level you can find, and then go away. It's that simple. That's all I can think of at present. Of course, these are just the methods I've employed or would use and if anyone might have a different opinion please let me know! Best of luck! Keep us posted!
Based on your low statistics on cb, i'd advise you to RS3 Gold slaughter chickens until 10 str., and then slaughter cows until lvl 20 str atk and def before even trying dungeoneering. Because the creatures there will heap you.. If you do not can kill them, you'll end up dying... At around 20 lvl melee, you will be able tank them enough.