Best quality second hand semi offroad vans on a 20k budget?

Rhys, Maybe rephrase that second sentence! Doesn't sound quite right.

Hi Rhys T1,

I don’t have much experience/knowledge of the other brands, however we have owned a Goldstream. They are well built, strong, and should serve you well.

Macca.

Hi Rhys,
Perhaps you could provide us with some more detail on what you intend to do with the new van? For example, will it be occasional weekends away, or are you intending to do longer trips? Will it be on smooth dirt roads only, or something more challenging?
In my opinion, having owned a Jayco Penguin, it's fine for weekends, and not too bad for dirt roads, but I wouldn't advise a Jayco pop-top for extended periods or any of their "off road" vans for anything other than dirt roads unless you are prepared to spend some time modifying and strengthening the van and its interior.
My daughter has a Coromal, and it's much better built.

Hi Rhys,
Another tick from me for Goldstream re: build quality and service.

I have a 2014 Goldstream Vacationer II pop-up very similar in size to the JAYCO SWAN in off-road guise.
Tows beautifully behind a MAZDA BT-50 ute.
It has not seen any really rough tracks because I think it is too big to do that and not damage stuff IMHO.
(yes - the MAZDA would get me there and back)
However, I spoke at length to another Goldstream owner last year when we crossed paths in SA on our way to Uluru, who had almost an identical pop-up to me and he had dragged it everywhere off-road in Nth Qld, NSW and VIC High Country and it had not missed a beat with regular servicing - name a famous track and he had done it.
Also, I have friends who have had JAYCO from new and if (when) it breaks, JAYCO fix it under warranty NP, minor things really, which doesn't really apply to you with second hand other than if the vans you are considering have had issues, they would have been fixed already so may not present again as a problem to the next owner.
Re: your budget, you will get more choice and perhaps a later build year or features if you go a JAYCO.

First pop-up van, with a really young family, you might not go full-on offroad unless you have some favourite spots to revisit, so family comforts might take precedence as all vans will go where you want if size, clearance and a-frame length are all equal. My tip is whatever you buy, ensure your mattress is Queen-size and has innersprings.
Regards,
Marty