The photo's I have seen of the Captains sim indicate to me it is little more than a toy.
I do NOT understand why someone with as much experience as this guy flying the real thing would build such a box, let alone use it! He could have used the Sim's at work, clearly he was senior enough to probably even bring friends in if he particularly wanted to.
I understand fighter combat sims and the like - they are good fun, but it is always acknowledged they are toys. In fact the 'good' sims to my mind are the ones that don't pretend to be anything else.
I accept there might be weirdo anorak wearing pilots out there who might want to make a cardboard (although cardboard is accurate, and most pilots have used them in basic training), milk carton, string and elastic band box painted to look like the one you are forced to spend 1000 hours a year in, but in 30 years I have NEVER met one personally. He clearly spent money on it, and for what it is its no doubt good, but if you have kids and don't fly I would liken it to something 'Mr Maker' on TV would create in comparison to a real FFS, let alone the aircraft.
That sim would give you basic terrain awareness - though no more than Google Earth and I would assume Flight Management Computer functions. NOTHING else would even remotely be like 'the real thing' nor even the 'real' MAS sim the guy could access whenever he wanted to. Any 'practice' he would get from that construction would be considered (IMHO) 'Negative Training'. In other words, using it would lessen your physical flying skills on the 'real thing'.
I strongly suggest you take a look at what is available online for anyone to purchase in 2014.
The PMDG simulators put most CBT's and FMC trainers to shame. Not to mention the platforms themselves have the capability to map the entire earths terrain using SRTM mesh (space shuttle data)
Plenty of commercial pilots use these products to brush up before a sim check.