I'm a little surprised. How would it not be dangerous? It's a tour through the Spinward Marches for starters.
Not all the worlds of the Spinward Marches are Wild Frontiers, and you'd expect a circus road manager to try to avoid them. Not just because danger is bad for business, but also because Wild Frontiers have a strong correlation to small populations, and cost of interstellar transportation would require playing on worlds where a lot of people can afford sizable ticket prices. (From the blurb it appears that the owner has somehow acquired title to a former navy battle tender and if he doesn't have a loan to finance, that side may be managable, but danger is still Bad For Business).
Much would depend on the size of the payroll. I get the impression that we're talking scores of performers and roustabouts at the very least. With each jump representing ten days of no income at all. So low-population worlds seems out of the question.
Picture performing for starters, failure to dodge a knife or even a simple tight rope walk could render the characters out of action but double it up with assasins, planets who do not like circuses and many unsavoury characters required to keep the circus going and I think you will find there's an abundance of danger to keep even the most psychotic of players on there toes. (A lot of action happens behind the scenes of a circus, especially an intergalactic one).
A circus will have lots of problems. But I'm not sure how many of them would be suitable for a small team of PCs to solve. For those that are suitable for PC-style solutions, a circus provides a plethora of talented NPC henchmen. Acrobats, sharpshooters, knifethrowers, strongmen, magicians, animal tamers, roustabouts... I think it would be a big challenge to come up with problems that can be solved by the PCs and the PCs alone.
For inspiration. Read E.E. Doc Smiths Family D'Alembert series and you might just change your mind.
I haven't read any of them (never came across the books), but I understand that the d'Alembert's are secret agents using the circus as a cover. That would skew the dynamics considerably, I think.
I recommend Barry B. Longyear's
City of Baraboo. It tells of an interstellar circus and the troubles it encounters on many different worlds.
Hans