Here are a few research notes & observations that I would like to pass on from years of work focused on the period that is roughly the first quarter century of motor sport in the United States that might be helpful to others.
Most of these are pretty much low-hanging fruit, tending to be a blinding flash of the obvious in retrospect, but not necessarily at the time, especially given the rather thin historiography of years ago.
The first season review that I have been able to discover in an American automotive journal dates from January 1906 and is focused literally on speed -- both in record or speed trials and on the tracks. It is important to realize, as I did very belatedly, that speed is rarely or not usually expressed in miles or kilometers per hour but more often than not in time, minutes and seconds and fractions thereof. Speed records, real or imagined or contrived, are a constant feature in these early journals and AAA Contest Board materials. Right up until its last season summary in 1955, the Contest Board devoted pages and pages to the international and national speed records.
Up until about the beginning of the Great War, considerable coverage was devoted to automotive contests such as hill climbs, reliability & endurance runs/trials, and tours. The were Big Events and deserve much more attention than they are usually given. I was slow to grasp their importance thanks to the usual presentist myopia that we tend to have regarding the past that we are not that familiar with.
With the Indianapolis Motor Speedway Hall of Fame Museum currently engaged in a preservation effort that involves the digitization of the AAA Contest Board, USAC, and CART material in its archives, it is possible that there will finally be alternative to the Contest Board material currently found only on the microfilm that the Atlantic Old Timers Racing Association had made in the mid-1980s will be available to scholars. Related to this, there is an ongoing digitization project for the Sports Car Club of America (SCCA) at the International Motor Racing Research Center (IMMRC) that should be boon to researchers.
The recent availability of digitized American automotive journals of the early 20th century has transformed the study of this period. While there are still issues with gaps and poor reproduction regarding the journals, it is now possible to use these journals for research without having to undertake an extensive travel program to find them.
Much work remains to be done on the AAA Racing Board and the Contest Board. There seems to be little of the original documentation of the Racing Board that has survived; however, there is much regarding the Racing Board's activities that can be found in the contemporary automotive journals.
Despite the herculean efforts of Darren Galpin and others, there still is not a good record of the automotive contests held in the United States from 1895 to the end of the 1920 season. Given the enormity of the task it quite possible that there may never be, but that this basic element of information is still very much missing in action is telling. Mea culpa, by the way. Also, this effort should conform with the contemporary practices of the time and not be forced to conform with boxscore practices of later days, which can distort the information. Also, one should avoid the boxscore/database mentality and adopt a narrative approach. You might be surprised at what you might notice.
There is a big -- as in Huge -- difference between possessing Information and possessing Knowledge. Accept that and continue to plug away with the realization that while research is endessly seductive, writing is still hard work (thus spake Barbara Tuchman...).
Accept that what you find will often be muddled and even contradictory at times, but gather enough sources and something close to what happened will emerge. Also, along this line, the contemporary writers actually do a better job than some would have you believe. Skepticism is always warranted, of course, but be careful that it does not become cynicism. Although whatever Russ Catlin has written should be approached with great caution, there are a few nuggets even in his articles if you look for them.
American motor sport during its early years was quite cosmopolitan in almost all respects.
This topic is wide open for research and work focused on infrastructure and other aspects rather than the usual overkill on the machinery and personalities. Or, rather the overkill on the Usual Suspects rather than the other often overlooked machines and people.
There is more, of course, but these are just a few ideas I wish someone had passed on to me Way Back Then...
Above all, Bibliographies and Footnotes Are Your Friends.