Hi Steve, can I say it's pretty brave of you to ask total strangers what bike to buy, not to put to fine a point on it we know nothing about you nor you us. Your best bet is to look up the bikes your looking at and read the test data that's available, usually these include any faults and good/bad points that the tester has found with the bike. Then it's down to aesthetics and what you like, colour and so on, take it out for a test ride and see if it suits you, other than that no one can say what bike suits you or your situation, with the best will in the world you might be 30 stone or 10 stone 6 feet tall or 4ft 6inches and all these things matter when it comes to buying a bike, the salesman/woman should if they have any sense at all tell you what might suit your budget and needs, one thing tho don't buy the biggest bike just cos it's big buy a bike that fit's on the back of your bus not one that lifts the front wheels off of the road. Other than that enjoy your trip and ride safe.
One other thing, if you have never owned a bike before buy from a dealer not some guy you met in a bar or from an advert in Craigs list, that way you have the backing of a guarantee that the bike will not chuck oil or fluid out over the road 10 miles down the track.