Huh! The Pilot 34 gives great access to the Yanmar 370 hp single engine. Maybe you have twins?
Yes, the forward valves are underneath the pilot house sole but it is easy enough to reach up and check them. The only slightly difficult thing is getting the valve cover off but it will roll off to the side.
And FWIW Tony Athens, the owner of Seaboard Marine in California, a Cummins and Yanmar dealer, thinks that 1,000 hour service on the valves is excessive, particularly if the recommended 100 hour check was done.