Really sorry I never replied to this. Unfortunately life got busy and I never got back to the story.
Anyway we spent our 6 months in Cambodia. I ended up buying a Suzuki Axello 125. We rode pretty much all over Cambodia. We also did a couple of trips to Thailand and also into Laos. It wasn’t too difficult to get the bike across borders. The most difficult was Thailand to Laos, luckily we met a fluent English speaking local who helped get us through.
It was totally impractical to try and get the bike into Vietnam but we had no problem hiring a bike there.
I’ve never decided if the worst part was contending with the crazy bus drivers in Cambodia or the muddy back tracks we encountered in both Cambodia and Vietnam! We learnt quickly that motor bikes are invisible to other drivers – be prepared for anything and always on high alert.
Cambodia has to be the only country in the world where it is illegal to ride in daylight with your lights on. I got stopped a couple of times by police telling me to turn them off. The locals were also always indicating to tell me they were on.
Thai roads were good, mostly dual highways so no problems with oncoming traffic. We did discover that you can’t ride bikes on freeways in Bangkok which made for some navigation problems there!
In Laos it was cows on the road, totally unpredictable!
We blew a tyre in the back blocks of Cambodia (Cardamom mountains) miles from anywhere. Got prepared for a long walk, walked about 10 metres and there was a isolated little house occupied by an English speaking police officer who helped us get to the nearest village and organized the repairs – amazing luck!
We spent some long days on the bike, Siem Reap Cambodia to Koh Chang Thailand in one day was a bit much but we made it. So was the trip through the Cardamoms from Koh Kong to Pursat in one day! They were both dawn to dark days. Another long haul which we expressed over two days was Pakse to Vientiane.
Anyway, that trip has certainly given me the urge to keep travelling. We are now planning a trip from SE Asia to Europe. Much more ambitious and a lot longer. Now trying to decide what sort of bike to get and all the logistics of border crossings. My wife still doesn’t ride so it has to be two up again! So I am going to start another thread for some help.