Hello! I looked up your posts about Llanallgo as that's also where my ancestors came from.
I was recently at the Records Office in Llangefni and was using a book which had an outline map of the parishes of Anglesey. Each one has a standard number and these are also the ones used on GENUKI
http://www.genuki.org.uk/big/wal/AGY/parishes.html . I asked whether it was possible to have a copy of the map, but the book was supplied by the Gwynedd Family History Society on the condition that it was not to be photocopied: however, there was no objection to my making a sketch-map. This is a bit rough and wobbly but it shows that Llanallgo (13) is enclosed by Penrhosllugwy (70) and Llaneugrad (29) with Llandyfrydog over to the west of Penrhosllugwy. Since returning home to internet access I've found that GFHS has made a map available on its website at
http://www.gwyneddfhs.org/There are some useful Calvinistic baptism records available through GENUKI at the link above, and you might also find FreeREG helpful
http://www.freereg.org.uk/search/index.htm as you search by county and parish.
I didn't get as long at the Records Office as I would have liked (2 afternoons -- could have stayed all week!) but I can't praise the staff enough for their helpfulness and interest, answering personal and telephone enquiries in two languages and providing information of all kinds from maps to microfiche.
While I was in Anglesey I also bought a map, not just to get about the island but to see the location of place-names that come up in research. It's OS Landranger 114, scale 1:50,000 so it should be available from OS direct or good bookshops.
It's a great place to spend a holiday -- oh, and I'm told you can also visit museums, theatres, beaches, go walking, climbing, shopping, riding, sailing, dine out etc if you're interested in all that kind of thing....
Hope you find what you're looking for!
Meryll