ive used the plug and play block when I first started and its very very easy to build a fast car. In fact if you get it with the legend cut then there is no other woodwork to do but perhaps give is a once over with fine sand paper to smooth it out, or if your like me now (I am copying what others here do after reading posts in the past) is use a vinyl covering or Monokote.....so much easier to just cut it out to fit the car, peel the back off and stick on the car....instant finish...smooth, no paint drying or bubbles or dealing with primer and resanding etc....and if you wanted to paint you can paint over it anyway.....
so you could literally finish the body of the car in an hour or two (just black sharpie any open areas or the sides ala Kinser!), then if your using axels from DD4H, and you have his polishing kits, this will take a most maybe 5 to 10 minutes per axel if your being careful and taking your time....
then the wheels, again with John's polishing kit its what 5 minutes per wheel going slowly and carefully to do the first polish. Second polish will take an overnight dry (put in, wait 10 minutes to dry, then buff out and let sit overnight to cure)....
Next day, take all the part throw it on a scale and now add the tungsten cubes to get the weight to as close to 5 ounces as you can and install the weights in the precut pockets...put 2 rows of 6 behind the rear axel, and likely one row of 6 in front of the rear axel and the remaining as a row shifted more towards the dominant wheel side)
Now buff in graphite into the bores (fluffy pipe cleaner or other non scratch bore applicators), spray pledge on the axels and final wipe off and let dry for a few minutes and then put wheel and axel together, add graphite to the two ends and spin or tap to get in down in the bores and broken in a bit and then install on car with a small gap (John also sells some nice gap gauges that are helpful if you don't like eyeballing it)...
Final weight of the car (don't forget to get some of that foil tape or other tape to cover the weight pockets up under the car) and use tungsten putty or lead tape or whatever to get the final weight to what you want.
if its drilled straight your done....if you had the body drilled canted for running the rail then just verify that the car drifts about 3 to 4" over 4 feet which it should as its drilled to do so already or just don't worry about it LOL.
so adding it all up....at most fairly straightforward work that even the boys can do a lot if most of with their parents help (which is what scout PWD racing is about!), spread out over a max 2 day period (unless you want to do much more painting and design which requires dry time) to make a very competitive fast car that in all likelihood is faster than anything else at a scouts race (except for those other families doing the same as you LOL)!