Want to get tons of bamboo and scrap in a fraction of the time with no cheating? Here you go.
Setting up a bamboo farm and harvest
The area just to the west of Pop Pops Shop has some ruins that are useful. There will be an NPC there initially. Do the mini-quest to get him out of there. You will want to have a lot of storage ready. DO NOT do this close enough to anything you have built that the falling trees can reach it or your stuff can get destroyed.
Then plant a ton of bamboo closely together. It is helpful to leave an opening big enough for a grenade to go through. I plant around 150 to 200. Then after they are grown (which doesn’t take long), toss a grenade in there and run behind one of the ruin columns to avoid getting crushed by the falling trees. There will be an enormous amount of bamboo falling. The trees will also hit each other and help harvest even more.
To buy grenades, go south to the Big Box Booms shop. See pic. There is a fast travel available to unlock.
To get scrap quickly, after harvesting the bamboo, craft and scrap the Bamboo Tool to your hearts content.
You can now have tons of bamboo for building and crafting. This made the game much more fun and freed up time for me to do other things ingame.