On today's roads and with aids such as satnav or knowing well worn route, if you're in good health and experienced it's not that big a deal.
40 years ago I thought nothing of a thousand mile ride back to Calais and it was lot lot harder back then. Lack of autoroutes and paper maps and notes.
I still do Surrey to Como in a day and Surrey to Bordeaux for Lunch. I've also done Amalfi back to Surrey via the tunnel in roughly 24 hours.
2012 Guildford to Bologna for a 5 minute collection and then to Chambery, in total a tad over 24 hours, then late Dinner in the Buffalo grill that evening, I looked wrecked and they gave me a bottle of wine after they asked where I'd come from
then slept for 24 hours in the appropriately named Brit Hotel 
I regularly worked 48+ hour stints before that with no mistakes or issues. 24 hours + on a bike with fuel stops and food and drink seemed pretty easy apart from 6 or so hours at high speed in the rain
Make your own choices!
40 years ago I thought nothing of a thousand mile ride back to Calais and it was lot lot harder back then. Lack of autoroutes and paper maps and notes.
I still do Surrey to Como in a day and Surrey to Bordeaux for Lunch. I've also done Amalfi back to Surrey via the tunnel in roughly 24 hours.
2012 Guildford to Bologna for a 5 minute collection and then to Chambery, in total a tad over 24 hours, then late Dinner in the Buffalo grill that evening, I looked wrecked and they gave me a bottle of wine after they asked where I'd come from
then slept for 24 hours in the appropriately named Brit Hotel I regularly worked 48+ hour stints before that with no mistakes or issues. 24 hours + on a bike with fuel stops and food and drink seemed pretty easy apart from 6 or so hours at high speed in the rain
Make your own choices!



) NO HID riding lights, NO cruise control, the list goes on.