Hello!

So I currently GM for a party playing Burnt Offerings the Pathfinder 1e adventure path. They are close to wrapping it up and will be level 4 by the end. I am going to suggest we make the jump from Pathfinder to D&D for all the obvious reasons. I just need a believable reason for a party to leave the nice seaside town of Sandpoint and head to the harsh frozen north. Could be they are tasked by someone similarly to the hook for Tomb of Annihilation. Could be they heard of something too tempting to pass up up there. I'm just struggling to come up with something that isn't just "so you guys head north for some reason". 

I will essentially be shoe horning Sandpoint somewhere along the Sword Coast. I might suggest the players transfer their characters to D&D at 3rd level because they will still feel pretty strong compared to PF and it will be better for RotFM.

Any suggestions would be hugely appreciated. Ideally I want it to feel like a natural option rather than the very obvious railroading I'm trying to disguise. This is the first group I have DMed so please be gentle haha 

Thanks!

Since this is the Forgotten Realms,, you can find many, many forgotten, inactive and/or randomly activating portals scattered everywhere.

Not knowing your actual starting area, I'll give you an example I have used more than once for my campaigns. A portal that activates randomly, in most cases one of the party members had a heirloom (signet ring) that activated it when they came in proximity. I usually have the portal open in a ruin at the other end. I usually make the portal one way.

You can fill in the miscellaneous details as fits your campaign.

That is a very fun idea! A little homebrew quest that explores a ruin and uncovers a long dormant portal.  Next thing they know they aren't in Kansas anymore Toto.

Another favorite trick I like to use is the party is walking down the streets of Waterdeep and it is their misfortune to meet a drunken mage who accident teleports them to some random, mistaken location. Then drops dead of age and alcohol (apparently/supposedly). The supposedly drunken wizard might also have been merely a simulacrum . . .

Have you looked at the "Icewind Mail" Encounters of the Week series?  I believe that will get you to 10 Towns.

This is the start of the encounter series (https://www.dndbeyond.com/posts/837-encounter-of-the-week-icewind-mail) but there is eight other encounters building up to RotFM. 

I haven't but I will check those out. Thank you 😁

Just sit right back and you'll hear a tale,
A tale of a fateful trip
That started from this tropic port
Aboard this tiny ship.

The mate was a mighty sailing man,
The skipper brave and sure.
Five passengers set sail that day
For a three hour tour, a three hour tour.

The weather started getting rough,
The tiny ship was tossed,
If not for the courage of the fearless crew
The Minnow would be lost, the Minnow would be lost.

source: https://lyricsondemand.com/tvthemes/gilligansislandlyrics.html

In other words, give them a sea quest and *boom* storm. Throw in a water spout with lightning, eldritch fire, and wights trying to board the ship while it's spinning in the wind. End at the frozen shores of whichever.

I like Wysperra's storm idea.

You could introduce an NPC who wants visit the north because of reasons (expedition, commerce, family etc.) and hire the party as protection. You can combine it with the storm which gives a reason to get rid of the NPC if you so wish (or not).

The storm idea could definitely work nicely. That could throw them straight into the wilderness survival side of the module. I could possibly use some of the icewind mail stuff too. Maybe the ship gets sunk by the skeleton shark so they get a taste for the undead aspects and then they could stumble across the hut that is being attacked by a yeti. This could be great!  Thanks everyone!!

The group I'll be starting the adventure for on Wednesday night is being primed for RotFM with the 'Icewind Mail' series, though I've cut several of the deliveries from it to keep it streamlined, and made a few other changes to keep the story line consistent to when the campaigns have their 'handover'. I also didn't want to start chapter one at level 1, so I think if they did a couple of the encounters of the week they'll be level 3, and will be ready to handle some of the less balanced encounters.

I'm not super into the teleportation or 'shipwreck in a storm' setups, given it takes away a lot of player agency in why they are in Icewind Dale during this event. Though that said, I was planning on having them survive and avalanche as they cross over the Spine of the World, so maybe I'm not much better. 

Level 4 starts chapter 2, which focuses on destinations outside tentowns. Make their travel about reaching an adventure site, using the hooks already in the module adapted to the party.

Afterwords, its difficult to get back, and Ten Towns is closer than any other settlements...

In ROTFM you (spoiler) learn about the purpose of the obelisks in the world. Activating the one in Ythryn will send you back in time. 
‘So (slight repurpose) your players find a piece of that obelisk somehow and activating the piece transports them to Icewind Dale. Now they have the added quest of figuring out what happened, finding the obelisk in Ythryn and attaching their piece back to the obelisk to return them to wherever they came from. 

2nd idea: characters are kidnapped by a Nautaloid. They wake up inside and find a way to cause the ship to crash. They jump out (parachute or feather fall somehow) before it crashes and land near one of the ten towns.