I am the Archivisr for a 200 year old Brass Band. I am importing the legacy recordings using Audacity 2.1 s/w along with Audio Technica Hardware (AT-LP120-USB with the AT-HS10-SV Headshell). The 78’s were recorded in the very early 1900’s. Is there any advice regarding the best settings and maybe enhancements for such old recordings and bearing in mind that they have a large dynamic range as with Orchestra Recordings?
and bearing in mind that they have a large dynamic range as with Orchestra Recordings?
That’s not a problem. The dynamic range capability of records is limited by the noise floor and digital (at 16-bits or higher) has much wider dynamic range capability. The musical dynamics (AKA “dynamic contrast”) is are a challenge for records because the signal-to-noise ratio deteriorates during quiet passages. But digitally, you should be able to “capture” exactly what you hear.
Audacity 2.1
Time to upgrade. 
The current version is 2.3.3. The older version will probably work fine for recording but if you need help, any suggestions we give you may not work.
maybe enhancements for such old recordings
You can “play around” with the equalizer effect. It will be difficult to find the “correct” playback equalization and the theoretically-correct equalization may not actually give the best sound anyway. So, IMO - It’s best to just do it by-ear for the best sound. The highest frequencies will just be noise so you can cut the highs, but again you’ll have to experiment to see what you can do without damaging the music.
Audacity has is an automatic Click Removal effect (filter), there is a manual Repair effect, and in some cases where those don’t work, you can zoom-in and re-draw the waveform to fix a “click”. The regular Noise Reduction is worth trying to reduce hiss and/or hum, but it usually works best with constant low-level background noise. (It won’t work for “snap”, “crackle”, and “pop”.) If the noise is bad, Noise Reduction can result in unwanted artifacts.
There are also special programs for removing/reducing record noise. There is a free automatic program called [u]Wave Corrector[/u]. I’ve also used [u]Wave Repair[/u] ($30 USD). Wave Repair is “manual”. You have to manually select the audio you want to repair, but in most (but not all) cases it can “perfectly” remove clicks & pops. It offers several different repair methods and one of those methods is to copy from left-to-right or right-to-left. That often works very well because often the defect is only in one channel, or it happens at slightly different times in each channel. And, it should work especially well with your mono 78’s if you have a stereo cartridge with a '78 stylus The downside with Wave Repair is that it usually takes me most of a weekend to clean-up a digitized LP so that’s probably at least an hour for each 78 (depending on the condition).