To find out how many miles were biked in total, we can multiply the distance of the race by the number of riders.
The distance of the race is 2 miles, and the number of riders is 794.
Calculating the total distance:
\[ \text{Total distance} = \text{Number of riders} \times \text{Distance of race} \]
\[ \text{Total distance} = 794 \times 2 \]
\[ \text{Total distance} = 1588 \text{ miles} \]
Therefore, the total number of miles biked in all is \( \boxed{1588} \).