Try one of the above destinations; you have come so far and it would be a shame not to!
Bangkok acts as the major transport hub for south-east Asia and you could consider building in any area or country into your stay.Extensions are handled by Essentiall Travel, a fully licenced travel agency who will organise all your travel details and arrangements for you.
Remember that the areas mentioned are only suggestions. For example you may prefer an extension with the services of a guide, would like to travel by train (difficult in Laos!) for a major part of your trip or spend the entire time sipping cocktails at a luxury beach hotel.
The prices indicated are for the example itinerary outlined and will always include hotel accommodation with breakfasts, transfers, taxes and flights.