Hello! I've come up with at least 5 different configurations to get from Portree to Oban via public transportation in the spring (and I'm sure there could be additional ones I've yet to discover), but I've narrowed it down to two that seem the easiest and also the most scenic:
Option A (leaning towards this, as it's the least hassle)
-7:30 Depart Portree via Citylink bus
-10:35 Arrive in Ft. William
-11:40 Depart Ft. William via Scotrail train
-13:27 Arrive in Crianlarich (51 min to transfer)
-14:18 Depart Crianlarich via train
-15:28 Arrive in Oban
Option B: (possibly more scenic?)
-6:30 Depart Portree via pre-arranged taxi
-8:00 (?) Arrive in Armadale
-8:30 Depart Armadale via CalMac ferry
-9:00 Arrive in Mallaig
-10:10 Depart Mallaig via Scotrail
-3 hrs. 17 min. for lunch and ?? (not sure what else there is to do with suitcase in tow, especially if the weather is unfavorable)
-13:27 Arrive in Crianlarich (51 min to transfer)
-14:18 Depart Crianlarich via train
-15:28 Arrive in Oban
The biggest pro of Option B is the train journey from Mallaig --> Ft. William (versus only being on the train from Ft. William --> Crianlarich --> Oban). But I'm not sure if it that justifies the extra hassle of trying to get to Armadale before the ferry departs? And the ferry could experience weather delays, which would throw Plan B into chaos. Would love to hear opinions if you've done any part of this route!