I’m a bit confused about all the options but I have 350k points and I’m looking to do a RTW trip with my partner and I. I understand the Oneworld Classic Flight Reward is one way to do this, and I’m just wondering if it is possible to, for example, include eg. London as one of the 5 destinations, then travel through Europe by train, and fly out of Europe to the next destination at the other end eg. from Istanbul?
Yes. Check out the point hacks round the world guide. What are you proposing is a surface sector - so you can have gaps in your itinerary between destinations.
An example of this could be:
Sydney → Tokyo → London | Istanbul → Sydney
Obviously you can add more destinations in between, but nothing in the rules say you can’t have any “gaps” within your itinerary.
To add, you have to add the distance of your surface sectors (“gaps”), to your itinerary distance and keep that under 35,000 miles in total.
In djtech’s example, you have to include the distance between London and Istanbul in your total distance.
And arriving into London and departing out of Istanbul only counts as one stopover as well.