If you decide to rely on gravel or even grass paths, make sure that your paths are at least 30 inches wide. Three feet is better. My new gardens on my 50 acre homesite will definitely take advantage of all the experience I gained in my previous one. Authentic appearance can be established with far less effort than just using a shovel and wheelbarrow or being plagued with constant weeding. Determine just how period you are willing to go before you begin.
Good ideas are small water troughs or basins, benches or perhaps a sundial.
The use of ancient standing columns, ironwork pot stands or birdbaths are mostly Victorian and Edwardian, so avoid them unless you can specifically document them. An excellent idea for gravel paths is to use coloured gravels to make flat designs in the manner of knotwork. This may either be loose raked or set in a concrete bed. Some period plants that add a great deal of interest and texture that one might not expect are artichokes, hollyhocks, tobacco. In order to be reasonably period in overall concept, some form of enclosure is generally customary.