Welcome to Warwick, MD. Please drive carefully and observe posted speed limits. The final can be found at N39 25.abc W075 46.def.
The given coordinates will take you to a historical marker which tells us about the inventor of the steam boat. Use the information given to find abc. For a, take the number of letters in the inventor's last name and subtract the number of letters in his first name. For b, add the last digit in the year of his birth to the number of miles north of this point where he was born. For c, add the number of letters of his position in The Potomac Company and subtract the sum of a and b.
Then go to N39 24.933 W075 46.805 to find another historical marker. The information given here will help you find def. For d, find the second time March is mentioned. Add the two digits of the day to the final digit of the year. For e, find the date given for May. Add together the first two digits of the year and subtract that from the sum of the last two digits. For f, subtract the final digit of the ultimate year given from the final digit of the antepenultimate year given.