Creating a big, detailed map

[holyhalo]

I recently started helping some friends with creating their world and when I saw their world map I took it upon myself to improve their current one.
After several tries, they seemed happy with the final result of the map and I'm quite proud of it as well.



Now, we sort of generally decided that we wanted zoomed in maps of each kingdom and the islands so we could show detailed information like roads, rivers, lakes, cities, forts,...
I'm not sure how I should begin with this. The problem is that the map I made is too small so it can't be used for a big map because zooming in on it pixelates everything and ruins the map. I tried to make a much bigger version of it, which I like as well, but it lacks all the details that I created(read:randomized) on the small one, especially the coastline and number 13 island. In my opinion, the landmass of the second map looks boring and created, whereas the first map seems convincing enough.


I hope that sort of explains the situation. Now, for my help/question. How should I go about creating a big map out of the small map so that it can be zoomed in on and people can see the details that will be added later on? Should I go with a big map and then let people zoom in and move around to look at things or should I go for a small map with set zoomed in areas (one kingdom, for example) and then have different maps for each bit?