Some questions to consider:
Marysville is 41 miles away from Sacramento. Marysville is 157 miles away from San Jose (using today's routes). The old Sacramento cemetery was established in 1849 - if Mr. Sampson was buried away from Marysville, why wasn't he taken somewhere like Sacramento?
Was Mr. Sampson transported to San Jose for medical treatment? It seems quite far for an ill man to have travelled such a great distance.
According to the internet, Marysville City Cemetery was established in 1850. Could he have been buried there? It seems unlikely, but could his burial records have been lost and possibly a (possible) hastily made headstone deteriorated over time so there is now no evidence of his burial?
Why did Charles buy calico to refurbish the place John was boarding. Was it to cover windows (maybe no glass in them) or, was it to replace sheets etc. after John died (incase what he had was infectious.)
I thought the following was mentioned in this thread, but I do not see it so perhaps it was discussed in another "early California" thread...
Mourning cloth/bunting was purchased for the house of a newly-departed person. I don't know why they would have used calico,
but the cost of the material seems too high to have been for simple household use, especially considering the costs of the other items mentioned.
"...I cannot easily read the writing, but also written on the page is:
"Carriage for J Sampson to? San Jose(?)" and possibly "$64.00"
Could he have been transported to San Jose, California for burial?
Does it even actually state "Carriage for J Sampson to San Jose - $64.00"?..."
...Wording from image 1403 (apologies for any errors - I'm not used to the penmanship style - some words are purely guesses) :
Estate of J. Sampson ? CB Sampson
Carriage for J Sampson to? San? Jose? - 64.00
Is there a possibility that "Carriage for J Sampson to? San Jose" is not the correct wording? It doesn't appear to be "from San Jose" but could it be something else? Perhaps he was in San Jose, became ill and was then transported to Marysville? Was the wording actually "San Jose"?