Here is my initial optimized route for the various versions, for anyone looking to push it down further.

TRS 80 COCO --

N, N, N, W, W, GET SHOV, N, KILL SNAK <WITH SHOVEL>, E, E, E, GET CANT, N, FILL CANT, GET CANT, W, W, DIG, GET TORC, N, N, D, S

DIG, GET MAGNI, W, W, N, S, E, DROP ALL, GET CANT, GO TREE, CLIM TREE, GET DATE, D, W, E, FEED CAME, MOUN CAME, RIDE CAME,

DISM, LOOK CARV, OIL SCEP, PULL SCEP, GET CANT, EMPT CANT, CLIM PYRA, GET AXE, D,

FEED CAME, MOUN CAME, RIDE CAME, DISM, GO POOL, FILL CANT, GET CANT, DRIN, CLIM STEP,

GO TREE, CHOP FRON, GET FRON, MAKE ROPE, BRAI FRON, W, E, DROP DATE, DROP AXE, GET MAGN, GET SHOV, GET TORC,

GO POOL, HOOK HOOK, TO HAND, PULL HOOK, UNHO HOOK, GET SCEP, DRIN, DROP CANT, LIGH TORC, WITH MAGN, GO DRAI, W,

FLOA BOAT, GO BOAT, PADD BOAT, PADD BOAT, TIE ROPE, TO BOAT, TIE ROPEl, TO POLE, GO ARCH, TRAN HIER, PUT SCEP, ON MUMM, DROP MAGN, DROP SHOV

GO CRAC, GET LADD, GO CRAC, GO ARCH, UNTI ROPE, UNTI ROPE, LOOK (until hole in roof), PUT LADD, CLIM LADD,

CLIM STEP, GET DATE, FEED CAME, MOUN CAME, RIDE CAME, DISMOUNT

APPLE II --

N, N, N, W, W, GET SHOV, N, KILL SNAK <WITH SHOVEL>, E, E, E, GET CANT, N, FILL CANT, GET CANT, W, W, DIG, GET TORC, N, N, D, S

DIG, GET MAGNI, W, W, N, S, E, DROP ALL, GET CANT, GO TREE, CLIM TREE, GET DATE, D, W, E, FEED CAME, MOUN CAME, RIDE CAME,

DISM, LOOK CARV, OIL SCEP, PULL SCEP, GET CANT, EMPT CANT, CLIM PYRA, GET AXE, D,

FEED CAME, MOUN CAME, RIDE CAME, DISM, GO POOL, FILL CANT, GET CANT, DRIN, CLIM STEP,

GO TREE, CLIM TREE, CHOP FRON, GET FRON, MAKE ROPE, BRAI FRON, D, W, E, DROP DATE, DROP AXE, GET MAGN, GET SHOV, GET TORC,

GO POOL, HOOK HOOK, TO HAND, PULL HOOK, UNHO HOOK, GET SCEP, DRIN, DROP CANT, LIGH TORC, WITH MAGN, GO DRAI, W,

FLOA BOAT, GO BOAT, PADD BOAT, PADD BOAT, TIE ROPE, TO BOAT, TIE ROPEl, TO POLE, GO ARCH, TRAN HIER, PUT SCEP, ON MUMM, DROP MAGN, DROP SHOV

GO CRAC, GET LADD, GO CRAC, GO ARCH, UNTI ROPE, UNTI ROPE, LOOK (until hole in roof), PUT LADD, CLIM LADD,

CLIM STEP, GET DATE, FEED CAME, MOUN CAME, RIDE CAME, DISMOUNT

ATARI --

N, N, N, W, W, GET SHOV, N, KILL SNAK <WITH SHOVEL>, E, E, E, GET CANT, N, FILL CANT, GET CANT, W, W, DIG, GET TORC, N, N, D, S

DIG, GET MAGNI, W, W, N, S, E, DROP ALL, GET CANT, GO TREE, CLIM TREE, GET DATE, D, W, E, FEED CAME, MOUN CAME, RIDE CAME,

DISM, LOOK CARV, OIL SCEP, PULL SCEP, GET CANT, EMPT CANT, CLIM PYRA, GET AXE, D,

FEED CAME, MOUN CAME, RIDE CAME, DISM, DROP DATE, DROP SCEP, GO POOL, FILL CANT, GET CANT, DRIN, CLIM STEP, DROP CANT,

GO TREE, CLIM TREE, CHOP FRON, GET FRON, MAKE ROPE, BRAI FRON, D, W, E, DROP AXE, GET SCEP, GET MAGN, GET SHOV, GET TORC,

GO POOL, HOOK HOOK, TO HAND, PULL HOOK, UNHO HOOK, GET SCEP, LIGH TORC, WITH MAGN, GO DRAI, W,

FLOA BOAT, GO BOAT, PADD BOAT, PADD BOAT, TIE ROPE, TO BOAT, TIE ROPEl, TO POLE, GO ARCH, TRAN HIER, PUT SCEP, ON MUMM, DROP MAGN, DROP ALL, GET TORC

GO CRAC, GET LADD, GO CRAC, GO ARCH, UNTI ROPE, UNTI ROPE, W x8 (to let boat drift), LOOK (until hole in roof), PUT LADD, CLIM LADD,

CLIM STEP, GET DATE, FEED CAME, MOUN CAME, RIDE CAME, DISMOUNT