To test all these things out, I generally make a light-weight webmap that can serve as a testing ground. Below is the result of the development of the Armed Forces Retirement Home (AFRH) Arches app.
Generally, there are suitable basemap layers out there somewhere. In this case, we used OpenStreetMap's default tile rendering for the street map, and a 2013 aerial photograph tileset published by DCGIS for the imagery. (In an earlier iteration, we used MapQuest tiles which was great because they had a separate "labels" layer that we grouped with the imagery to make a very nice-looking hybrid layer. Then MapQuest discontinued their tile service. Bummer.)
The more interesting part of the process is always the creation of the historic map layers. Legion GIS was provided with 12 high resolution scans of these maps, ranging in date from 1850 to 1975, and then the fun began. Full details on our favorite image processing techniques are for another post, but through some GIMP processing, ArcGIS/QGIS georeferencing, and GDAL resampling we were able to create nice, as-light-weight-as-possible GeoTiffs. These were published as Web Map Services through GeoServer, and the result is shown below.