Honda say 8 hours to change a crank which is the biggest strippdown imaginable, double for inexperience add 4 for corroded fittings and add 2 for gasket surface and inner cleaning gives you 22 WORKING hours for you assuming you have a decent 3/8 drive six sided socket set. QUALITY circlip pliers, torque wrench, proper workshop manual, some sort of cleaning bath with scrapers and a budy to assist with the lift out. Oh and all the bits you need.
If you are doing a full strip you will need a full gasket kit, full oil seal kit and advisedly a cam chain and primary chain as a minimum list