Looking back on the two adventures (I've already ran them) I'd agree there are some railroad elements. However, they are at least dramatic railroads. Namely the two that stick out are Journey's End and the shipwreck.
For the SWW I highly recommend that the PCs are in charge of the ship. When I started the campaign I provided 4 extra 'occupation' skill points for professions and knowledges and did make clear that nautical elements would be prominent. So one PC was the Captain and the other the Navigator. The NPCs for those roles became aides of sorts to the PCs for those tasks.
The NPC cast goes a long way to keep the journey interesting and unexpected events flowing. For instance, the Avner character underwent a lot of changes as the cleric was intent on 'rehabilitating' the cad and making a hero out of him. It took a long time and many attempts but ultimately Avner did become a better person and even figured prominently in the defense of Farshore against the pirates in TOD.
Journey's End is unavoidable but my player's did enjoy that section a great deal. The creepiness of the situation and finding the source of the problem gave them enough hooks to go along with it.
The shipwreck was tweaked slightly as the party was responsible for navigating the ship so they could at least beach it near the shore and keep the damage to a minimum (making the restoration of it easier once they obtained supplies from Farshore). The party still felt their actions were influencing the outcome of the event.
As for HTBM when I ran it the players spent along time conferring on the beach as to what to do. They talked about building rafts, heck even hangliders. In the end they did take the overland route (mainly because the cleric was tired of sinking in water with his full-plate). So again I felt my players had choices and options.
Overall it really depends on the group and the DM's willingness to improvise, embellish the written material and keep the game enjoyable. Both of these adventures were amongst my favourites to run in the path though TOD was probably my favourite.