I have a house built in 1959 that has a whole house fan. The fan is not wired with a firestat. I understand the saftey features of having it, but is not having it a violation of code?

I need to install electricity in my garage by connecting to my main box in the basement of my house. I hope to bore a hole in the basement wall and run conduit to the garage. The circuit must handle a fluorescent shop light, battery charger for boat batteries, and occasional use of small tools. I want safety and economy. Provide insight to any thing I overlooked. Circuit length 170 feet Voltage 120 House voltage on 120 reads 123.5. Amperage ???? Is a 20 amp breaker adequate since I have 2 Sylvania GTE breakers from a 220 well pump no longer used that I think I can separate. Wire size ???? If an 8 or 6 is required will it connect to the breaker directly. What do I do to connect it to a 120 receptacle and the light switch and light? Could I get by running two large individual wires from the main box and running a ground to a rod at the building or must I run a ground from the main and put in a ground rod also? Wire type ???? Based on wire size etc. Number of wires ?? Schedule 40 Conduit size ???? The route taken will require a 120 degree turn about 70 feet from the house. What is the best approach to installing it, all at once and fish or section by section? Conduit depth ????