Pound for Pound, Dollar for Dollar, the Hauler is the best explorer in the game, hands down, the ASP maybe the best in terms of absolute range, but a 6 mill + price tag and that is just for the hull, equipping it, your gonna probably drop another 12 to 14 mill on what, another 5 lightyears. Totally not worth it.
Until they have the ability have your friends come on board to take the second seat, and design a mechanic that will improve the experience by having a second person on board, the Asp is not worth it. I would even say the Adder is not worth it because you can squeeze just a tad bit more out of the Hauler's FSD in terms of distance.
Seriously, go with a hauler and equip it it with the best FSD, Powerplant, and Fuel scoop, get a detail surface scanner and a Advanced discovery scanner and bam your done.
my build if your interested.
http://www.edshipyard.com/#/L=30V,,2-3I3m3I2C2C2C3c,4zM2jw7OW2UI