Welcome to Sunline Owners Club! We hope your quest to find the perfect Sunline for you is a good one.
I echo what Wannabe's has stated.
I'll add, the Sunline brand is a good one. They are better then most and still better then many new campers built today!! That said, what the prior owner has done for it and how they kept it can be the difference between a great buy and one that will require a fair amount of work to correct.
If there are new tires, a new awning and a working solar panel, those items are of higher value can allow extra cost that is not normally reflected in the used camper prices. They themselves can be over $1,000 US. The solar is a bonus and new tires and an awning are common maintenance items.
It sounds like the prior owners have kept good care of the unit. But, they may or may not know the in depth way a water infection can happen. Just because they have not "seen" leaks in the camper does not mean one is not present in the walls, ceiling or floor. Hidden water damage will be your biggest concern as it can take a fair amount of labor to correct.
I "think" your 94 camper has a rubber roof. I cannot recall the change over date on the size of campers when they did the total conversion from metal to rubber. SunlineFan told us earlier this year, but I can't find his response right now.
You can tell a lot about leaks and care for a camper from the roof. The prior owner may have done everything right for the roof, or not as they may not have known what to do. This is an area to check out. Here are a few posts which can help explain and show what your looking for.
This post also has a link to a 2004 T-1950 which had no care done on the roof.
The moisture meter is a valuable tool when looking at a used camper and recommend you get one if your looking at a used camper. It can see things the prior owner may have never known. You can inspect the camper for a water infection that is trapped in a wall, ceiling, floor etc. By inspecting the inside, you can see into the walls, floors and ceiling for trapped moisture.
On the outside, you need to get a step ladder and from the outside perimeter only, (do not climb on the roof) look at the roof and all the sealants. If the roof is metal, it still has roof sealants that can breakdown. If the roof is a rubber roof, the sealants are the number 1 weak spot that leaks start in if the prior owner never knew about the routine roof inspections which needed to be done. If they never washed the roof very much, this is a concern as the dirt/mold and then lack of sealant maintenance will create leaks.
All this does not mean do not buy this camper if you find a leak area, but it will mean, do you have the ability to repair it yourself? If you have wood tools and the place/time to do the work yourself, all things in a Sunline are repairable. The materials are not that expensive, however hiring out the labor to do so, is. In most cases, hiring out rot repair for a large repair quickly becomes cost prohibitive at standard shop rates of $100 to $125/hr.
If you really like this camper, and the moisture meter turns up an infected area, get some pictures of the area with the problem and about how large the area is. Post them and we can help explain some of what you will be up against. Again the owner may have no knowledge they even have a water infection, but showing them the area may help you lower the price if you really want this camper and can do the repair yourself.
Hope this helps and good luck