You can teleport players to entities and armor stands are entities so they're good markers for this purpose. Place an armor stand and name it with a name tag (such as 'pos1'). Then you can teleport the player to the armor stand with the following command.
/tp @p @e[name=pos1]
If you want to move the armor stand without having to replace and rename it, you can teleport the armor stand to your current position.
/tp @e[name=pos1] @p
If you don't want the armor stand to be visible you can grant the armor stand an invisibility effect with particles disabled for a really long time.
/effect @e[name=pos1] invisibility 99999999 0 true
If you wish to remove the armor stands you can kill them easily with commands
There are limits to this method. Armor stands far outside render distance won't be picked up by the selector. For the default 48 chunk render distance that's in my tests it was something like 870 blocks or so which is pretty far. If you need more than that you can resort to adding /tickingarea