Place lots of small temporary ladders up and climb them .
Example you can see some I have left there. agree it could use a push and pull structure item like using numblock 8 to push it up or 2 move it closer. This could save all that extra building and deleting. I have suggested it but Valheim is still in early stages.
https://steamcommunity.com/sharedfiles/filedetails/?id=2417628896