It's over 10 years since I was there so obviously any info I have is not only out of date but subject to a faulty memory.

In my opinion I would be very reluctant to leave a van behind anywhere there unless you can arrange lock-up storage. The roadhouse at Gregory Downs may have some more info. Alternately you could store your van at Cloncurry.

Check http://www.adelsgrove.com.au/ for Lawn Hill accommodation.  They may be able to give you an update on road conditions too.

Many people take conventional vans in to Adels Grove, via Gregory Downs. Mt Isa residents take ordinary two wheel drive cars in there for the weekend, etc. By August, though, the remaining sections of gravel road may be corrugated - or there may have been a late season grade done. It is about 90km from Gregory to Adels and some of that is now sealed, so you would not be looking at a great distance off the blacktop.
I strongly suggest you phone Adels Grove and ask them how much is still unsealed. They will also be able to tell you about leaving the van at Gregory, if you still decide to do that.
Adels offers three different types of accommodation for those without their own. 1. donga type cabins - made up beds, shared verandah DBB. 2. Safari style tents with beds made up DBB. 3. safari style tents with made up beds but no meals in the package - a BBQ firepit though. You can take your own cooking and eating gear, and food, or hire a basic pack. All accommodation has to use the amenities blocks - no ensuite facilities.
My pick, would be the safari tent, DBB, package - and if there is a vacancy, pay a bit more for one of the creek front tents - magic setting.
An issue you would face is that you really need more than just one night. There are some great walks at the National Park, from less than an hour to several hours. A must-do is to canoe up the Gorge - even if you have never canoed before, the hire canoes are really stable, Lawn Hill Creek is a millpond and it is easy. Adels runs a really worthwhile half day tour down to the Riversleigh fossil Site D and the Gregory ford. Even just veging out at Adels is special.
We have worked at Adels for parts of several tourist seasons, but have not been back since 2006, so that is why I don't know how much of the road is still unsealed. It is one of my favourite places in Australia.

Lawn Hill '07



Cheers,
Peter