Estimate how far you need to drive with your road map. Road maps usually have mileage markers that indicate the scale of your map.
Figure how fast you are going to drive on the road and adjust your estimates based on the roads you are driving on. After all, you can't drive 80 mph on a surface street.
Do the math. Based on the speeds that you will be driving throughout the trip and the number of miles you will be driving for each speed, estimate how long it is going to take to get to your destination.
Figure out what time you expect to leave and get there, based on the result you got from Step 3. If you leave at 8 a.m. for a five-hour trip, expect to get there at 1 p.m.
Figure out what time you want to get to your destination and compare that to your estimated arrival time. This will permit you to make stops along the way for meals and breaks.