copper plated grp board can add its own capacitance here and there, often showing up as unwanted tuned ciruits where you have difficulty determining where. even component leads can become tuned and generate harmonics
terminations at freq are critical to maintain stability and purity of signals, as impedance matching is critical to retain maximum energy xfer along the signal path, even if its as short as the distance fromi nput to the output of an amp. consider the amp module itself as a 'line' with gain
proto/wire to grp is a challenge even for experienced designers since there is so much change as you migrate
use standard via widths/spacings, plentiful ground planes, thru vias to connect the grounds.
leave NOTHING to chance, or it will come back and bite you later like a reflecting wave from the end of the line...