A remaining challenge in the theory of polymer solution dynamics is associated with establishing a relation between the macroscopic hydrodynamic properties of polymer solutions and the molecular structure of the polymer and solvent. This problem is unsolved even for the simplest case of polymer solutions at "infinite dilution". Recent studies have focused on technical problems such as the "preaveraging" approximation, e-expansion truncation errors, and the influence of ternary excluded volume interactions which limit the accuracy of analytic calculations. The present paper examines the role of polymer excluded volume in altering intramolecular hydrodynamic interactions and the possible significance of dynamic chain flexibility on hydrodynamic polymer solution properties. This investigation is aided by analysis of our previous renormalization group (RG) computations and simple exactly solvable models, We also examine experimental trends for the variation of the polymer hydrodynamic interaction with solvent and the variation of the translational friction of small molecules with molecular size.