I did a fairly similar route last month.
Day 1 strava.com/activities/332147255
Day 2 strava.com/activities/332147230
Day 3 strava.com/activities/332147316
Day 4 strava.com/activities/332147336
Day 0 - Train to Harwich for night sailing to Hoek van Holland
Day 1 - Hoek van Holland - Haarlem.
Day 2 Haarlem - Den Oever
Day 3 Den Oever - Lemmer
Day 4 - Lemmer - Zwolle
Day 5 - Train from Zwolle to Hoek van Holland (you need to buy a bike ticket at the station) for afternoon sailing to Harwich. Train to London
We got a rail/sail deal (£120 each, including mandatory cabin for night sailing), which includes the return train to Harwich and return train to ANY station in Netherlands.
One thing that caught us out is that you can't take a bike on the rail/sail anymore, so we had to pay £4 each or something each way. Plus they hated us. Apparently you can book and pay for the bike over the phone or something. Anyway, we made it after some faffing.
Got a fair old head wind for most of the trip (it changed direction when we did!).
Day 1 was also rather a lot of the same stuff - rolling through dunes behind dijks with no view of the sea, but not entirely unpleasant... Haarlem is well worth a stop. We stayed in a lovely hostel - helloimlocal.com/
I've been to Haarlem twice and loved the vibe. They also have a great local brewery called Jopen. It doubles as a bar and is in a former church.
Got 15 min train in to Amsterdam that evening for a pootle about and some dinner.
Day 2 was pleasant. - camped in a tiny quite campsite in someones back garden.
Day 3 - I personally found the Afsluitdijk (all ~35km of it) to be pretty dull and tiresome. I wouldn't do it again. But I guess it's a means to an end, as there's some nice stuff on the other side. Hindeloopen is pretty and good for a beer in the sun on the water front.
- camped in a small but pleasant campsite on outskirts of Lemmer.
Day 4 was grim and wet. Horizontal sheet rain for hours, but the scenery was pretty.
- camped in big corporate campsite (very pleasant actually) on outskirts.
Anyway, I can probably dig out the campsite names if you would like.
Have a great trip!