Upper bounds on eigenvalues of PSD matrix?

Yes, it is true that the largest eigenvalue is bounded by the largest absolute row sum or column sum. You can check Gershgorin circle theorem. Actually, all the eigenvalues lie in the union of all Gershorin circles.

Also the fact that $\rho(A) \leq |\!|\!|A|\!|\!|$ can be helpful here (i.e. the maximum modulus of an eigenvalue is bounded by any matrix norm).