Sure, When preparing for the nether have around a stack of food, and maybe a back up shield. Also you might have to make a new portal in the nether if the fortress is too far away. For the end fight, take a little when you first get there to crit out some endermen for pearls. Then you can shoot the lower crystals, for the higher ones pearl up to them and the block clutch, or if you get stuck in the obi place water to get out. When he pearches, place a boat, and drive it into the bedrock, then you cant be launched and you can still reach his head.
For getting an end city, you need a lot of blocks, so you can return to the nether for netherack, or mine endstone. There are a couple types of end city that have no chests, only shulkers. Avoid those unless you want shulker shells. The only ones with the elytra is the end ships.