its easy if you're mobile/driving (10 min drive and i think there may be free parking in underground carpark by main lifts a hundred yds or so from main tourist place where hand registration stuff out)
not sure if they'll let you on lifts from Morzine to go and register (you'd not get packs til 8.30am or so and might not make it all the way round fully back to Les gets)
you can ride up to Les Gets but its 4 miles or so of slightly uphill riding
i've just taken ages registering 3 of us at Les Lindarets (new system still pants as couldn't add riders later like it said – had to enter them as user account details on site and then go to registration bit!)
might be best to try and get to Les Gets early and one or two guys pick up packs and then start from Morzine