Me (45 yr bloke) + Mrs V (43 F) + V Jnr (13yr gurl) did a weeks cycle touring of the Netherlands in August
I can cycle any distance, Mrs V has been doing a 10 mile commute in the recent past and V Jnr had been on a cycle holiday with her school
To work out the route beforehand I looked at the "Long Distance" LF cycle paths
Park car at Harwich, bike onto Ferry
Max mileage per day was 60km. Trains were used for bridging longer distances. This was pretty much the limit for Mrs V and V Jnr
All accommodation was prebooked "Stay OK" Hostels
Once we got there we realised that the easiest way to navigate was with the VVV cycle maps, see
http://www.vvvfietsrouteplanner.nl/ The little numbers on the map are excellently and reliably signed pretty much all over the Netherlands.
We went Hook of Holland up the LF1 to Nordwijk, stayed two nights. Then continued North to Heemskerk, stayed the night, back to Haarlem, took the train to Suid Soest, two nights in Soest explored the Utrech area, train to Rotterdam, stayed over night had a day in Rotterdam then back to the ferry
We were lucky with the weather in August. Didn't get rained on at all. But apparently August normally has lots of rain.