A solution came to mind almost instantly.
The [Absorption Rune: Null Drift] was already a type of mana gathering rune, designed to gather leaking mana.
I just had to connect it to the Warp Point.
I got to work.
Using fairy dust, I drew Connector Runes between the two main runes.
These were very basic runes, not even considered Apprentice-level.
Once that was done, I drew a Disguise Rune over the whole array.
It wasn't perfect invisibility, but it would hide the presence of the Rune Array from anyone who casually looked — even if they were skilled in magic detection.
'Finally done with this side.'
I activated the portal again, and stepped through it, reappearing inside the cave.
I repeated the same process there.
First, I drew another [Absorption Rune: Null Drift].
Then I connected it to the Warp Point with a fresh set of Connector Runes.
Lastly, I masked the whole rune array with layered Disguise Runes.