Unfortunately, it is pretty labor intensive. The good news is that FGG is working on putting its material into World Anvil. I'm not sure where Tegel Manor fits on the timeline, but I would get it on WA in a heart beat rather than having to data enter such a large adventure into Realmworks.
Also, I believe that Tegel Manor will be available in Fantasy Ground soon. I don't have enough experience with FG to know how well it works for navigating and using adventure content beyond the maps. However, having the Tegel Manor maps all prepped for VTT use might be enough to justify the cost of buying FG and the Tegel Manor content on it.