Fiennes never married and in 1691 she moved to London, where she had a married sister. She travelled around England on horseback between 1684 and c.1703, "to regain my health by variety and change of aire and exercise" (Journeys). At this time the idea of travel for its own sake was still quite novel, and Fiennes was exceptional as an enthusiastic woman traveller. Sometimes she travelled with relatives, but she made her "Great Journey to Newcastle and Cornwall" of 1698 accompanied only by one or two servants. Her travels continued intermittently until at least 1712 and took her to every county in England.A Vision of Britain Through Time has excerpts from her books:
I went to see Hampton Court 10 mile from London; it looks Like a little town ye buildings runn so great a Length on yeground, Ye old buildings and ye New part wch King William and Queen Mary built. Ye Queen took Great delight in it. Ye new was but just ye shell up and some of ye Roomes of State Ceil'd but nothing ffinished. The roomes were very Lofty, round a Large Court and all the appartments intire. The old buildings were on the other side the priory Garden: there was the water Gallery that opened into a ballcony to ye water, and was decked with China and ffine pictures of ye Court Ladyes drawn by Nellor. Beyond this came severall Roomes, and one was pretty Large, at ye four Corners were little roomes like Closets or drawing roomes, one pannell'd all wth jappan, another wth Looking Glass, and two wth fine work under pannells of Glass. There was the queens Bath and a place to take boat in the house. The Gardens were designed to be very ffine, Great fountaines and Grass plotts and gravell walkes, and just against the middle of ye house was a very large fountaine, and beyond it a large Cannal Guarded by rows of Even trees that runn a good way. There was fine Carving in the Iron Gates in the Gardens wth all sorts of ffigures, and Iron spikes Round on a breast wall and severall Rows of trees.Her style is somewhat breathless but has a charm all its own.