Dear Newbie is excited to have been given a great gift, a reprint of an historic cookbook. She questions if it could be taken to an event for reference, since copying out the recipes is tedious.
Let's consider this question.
Cooking knowledge is a sticky situation due to the nature of how foodways are learned "in real life." Everyone must eat, so from the start everyone has someone in their lives cooking. Recipes are introduced, become trends, become classics, and pass from fashion... or morph into something new as technology changes the way we cook, acquire ingredients, and experiment with substitutions.
Assume an interpretive focus of 1859-1865. In theory, any recipe published or traced to before 1865 should work; but does that accurately reflect the foodways of your portrayal? In many cases, it does not because your portrayal did not gain the sum total of your foodways knowledge in a single dose from a single source.
I'll give an example from my modern life:
A holiday tradition in my family is the breaded fresh ham sandwich. A basic recipe is thin-sliced pork, dipped by turns in cracker crumbs and egg-milk mix, and fried. I learned this dish from my grandmother who used "fresh ham" and saltines crackers, fried in vegetable oil in an electric skillet. When she had news that she and grandpa should reduce salt and canola oil became the new healthy alternative to straight vegetable oil, she switched to no salt saltines and canola oil. My mother thought butter crackers would give a richer flavor, so she used those instead of saltines. I am often unable to find "fresh ham" and must substitute a pork loin. I accommodate a friend with Celiac disease by using gluten free herb crackers akin to butter crackers. I dislike frying because the oil spatters, so I oven fry my breaded "fresh ham." Were I to trace this family recipe back even further than my grandmother, would I find ship's biscuit or bread crumbs for batter, frying in oil or lard or butter?
Were I, my late mother, and my late grandmother to publish cookbooks, we'd each have a very different recipe for this one "classic" dish.
In the mid 19th century, cooking knowledge was similarly acquired. You were taught basics as you grew up that reflect your family and their traditions. Situations such as health or availability caused substitutions that may have changed how your descendants would learn the recipes they watched you make.
So how does that help us judge recipe books for interpretive purposes?
Consider your event goals, not just over-all interpretive strategy that governs how you approach the hobby, but the interpretive goals of each event you attend.
If your goal is a survey of era appropriate recipes for your own edification, then learning several recipes from a book in which the instructions seem clear is an excellent introduction to historic cooking.
If your interpretive goal for the event is to showcase foodways of 186x generally speaking, then you can include a survey of books published in several dates prior to 1865. Showing 1820s & 1830s recipes that have become "classics, 1840s & 1850s recipes that are "family staples," and a few from 1860s that show the "newest trends" and "innovative technology" provides a solid context for the accumulated foodways knowledge of an average person of 186x. In short, bring the book if published 1830-1865.
If your interpretive goal for the event is to "Live as people of 186x for a weekend," then your specific circumstances need to be considered. Take your age and pinpoint the year your portrayal was born if the event date 186x was "today." Pinpoint the years for ages 10, 20, and the years you would have married or begun your own household. Pinpoint the years for major changes in circumstance, such as a big promotion for your husband that requires more fashionable entertaining to maintain "Place" or a season or two after imported goods become scarce. These years will be your targets for which your foodways knowledge would shift. Again, you're separating into three categories: "classics," "family staples," and "fashions, innovations, & substitutions."
I am 42 years old and let's take 1862 as a target date. I would plan my menus to use memorized recipes published 1800-1845 to reflect those I would have learned from watching my female relatives growing up, I might reference a "well loved" reproduced recipe book published circa 1845 for a complex recipe to reflect those that have become family staples I would make every-day, and if entertainment is involved I might include a clearly trending recipe from a reproduction of a barely used 1861 book or 1861 clipping from a magazine.
In short, choose the book carefully based on who you portray.
With a wealth of period cookbooks available online in digital collections and being reproduced by specialty publishers, we're able to think beyond convenience to add depth of knowledge to our portrayals, if we remember that foodways are an accumulation of knowledge and practice rather than created full formed in a single go from a single source.
Online Chronologically Organized Cookbook Collections:
The Feeding America Project
Historic Cookbooks Collection 1800-Civil War
Manuscript Cookbooks Survey