Overall
Truman: 49.55%
FDR: 53.39%
Truman ran ahead of FDR in Colorado, Indiana, Iowa, Kansas, Kentucky, Massachusetts, Minnesota, Missouri, Nebraska, New Mexico, Oklahoma, South Dakota, West Virginia, Wisconsin, and Wyoming
Here's the split for the top 5 counties and bottom 5 in some of those states
Top 5
Colorado: 51/49 Dewey in 1944, 52/46 Truman in 1948 (54% and 55% of the vote was in those 5 counties)
Top 10
Indiana: 51/49 FDR in 1944, 52/47 Truman in 1948 (45% of the vote)
Iowa: 51/48 FDR in 1944, 53/45 Truman in 1948 (32% and 33% of the vote)
Kansas: 55/45 Dewey in 1944, 49/49 Dewey in 1948 (156796/155516). [39% and 40% of the vote]
Kentucky: 57/43 FDR in 1944, 55/43 Truman in 1948 (33% and 36%)
South Dakota: 55/45 Dewey in 1944, 50/49 Dewey in 1948 (38%/39%)
Wisconsin: 55/44 FDR in 1944, 53/43 Truman in 1948 (51%/52%)
Top 15:
Missouri - 55/45 FDR in 1944 and 60/40 Truman in 1948 (58% and 60%)
The Rest of the counties
Colorado: 56/43 Dewey in 1944, 52/47 Truman in 1948
Indiana: 55/43 Dewey in 1944, 52/47 Dewey in 1948
Iowa: 54/46 Dewey in 1944, 49/49 Truman in 1948 (Truman 341906, Dewey 341788)
Kansas: 64/36 Dewey in 1944, 57/42 Dewey in 1948
Kentucky: 53/46 FDR in 1944, 58/40 Truman in 1948
Missouri: 53/47 Dewey in 1944 and 56/44 Truman in 1948
South Dakota: 60/40 Dewey in 1944 and 53/46 Dewey in 1948
Wisconsin: 57/42 Dewey in 1944, 50/48 Dewey in 1948
In conclusion: That Truman fella was popular in the smaller towns.
Campaign stops in those states
http://www.trumanlibrary.org/whistlestop/50yr_archive/jsmap1.htmColorado: six stops over two days
Indiana: 17 stops over six days
Iowa: eight stops in one day
Kansas: one stop in Junction City
Kentucky: 13 stops over two days
Massachusetts: no stops
Minnesota: six stops over two days
Missouri: ten stops over six days
Nebraska: no stops
New Mexico: two stops in one day
Oklahoma: 19 stops in 2 days
South Dakota: no stops
West Virginia: six stops over two days
Wisconsin: nine stops over two days
Wyoming: no stops