You could make him feel at home by removing the receptacles from the loo
UK power is 230V 50Hz, with 3 wide square prongs. You could buy a few UK-style outlets, and connect them 240V 60Hz 15A, which would make plugging british-corded appliances easy to plug in, but code compliance becomes an issue since finding UK style outlets listed for 60Hz may be a challenge.
To "properly" do it, you could install a central frequency converter and 50Hz panel which then could distribute to outlets throughout the house. Very very few devices are frequency sensitive, though, and it's less of an issue running 50Hz equipment on 60Hz power than vice versa so this is just overkill. (going the other way, 60Hz transformers can saturate at 50Hz and must be derated to 80% if we want to run US stuff overseas.) Nothing you mentioned would be a problem at 60Hz. Computers and train sets rectify to DC, and incandescant lights are not frequency sensitive. The PC just needs a US cord (cheap) or plug adapter (cheap) and to flip a switch on the PSU to 115V. You only need to provide 230V power to the lamp and train, which can be done cheaply via small cord-and-plug transformer with no electrical mods required.
For reference, US military bases overseas often have 120V 50Hz US-style outlets installed for convenience. I've never had an issue, even with items only listed at 60Hz. Except when overloading those pesky shaver outlets in european hotel rooms, the ones fed from some tiny-ass isolation transformer that even my digital camera sends into a constant blinking charge cycle and can't be good for the battery. Man, you'd think they'd have a bit beefier transformer in those...
