Here is a cover letter as shown except for the date location (maybe someone can advice us on how to change its location unless that doesn't matter).
In the main document, you add \usepackage{pdfpages} and where you want the letter you put \includepdf[pages = 1]{coverletter.pdf}. The pages = option is what page you want to insert the cover letter.
Here is a link to the package documentation: http://www.ctan.org/pkg/pdfpages
\documentclass[11pt]{letter}
\usepackage{newcent}
\usepackage{lipsum}
% Margins
\topmargin = -1in
\textheight = 8.5in
\oddsidemargin = -10pt
\textwidth = 6.5in
\let\raggedleft\raggedright
\begin{document}
\begin{letter}{
My Name\\
U of Research\\
Some address\\
Some city, state, and zip code\\
Some phone number\\
My e-mail address\\
\medskip
Dr. John Edit\\
Editor-in-Chief\\
\textit{Journal of Science}
}
\signature{
My Name\\
Professor, Dep ...\\
U of Research
}
\opening{Dear Dr. Edit:}
\lipsum[2-4]
\closing{Sincerely,}
\end{letter}
\end{document}
Here was a sample main.tex I created.
\documentclass{article}
\usepackage{lipsum}
\usepackage[final]{pdfpages}
\usepackage{tocloft}
% this section enclosed was lifted from Alan Munn
\usepackage{fancyhdr}
\fancyhf{}
\renewcommand{\headrulewidth}{0pt}
\pagestyle{fancy}
%-------------------------------------------------
\cfoot{\thepage}
\begin{document}
\cleardoublepage
\tableofcontents
\includepdf[addtotoc = {1, section, 1, Cover Letter, coverl}, pagecommand =
{\thispagestyle{fancy}}]{coverletter.pdf}
% addtotoc has {section number (first so it occurs after the toc,
% type it could chapter, section, etc, level refers to chapter...,
% the name in toc, and reference label
\section{Two}
\lipsum[1-3]
\end{document}
Since this was 3 pages, I had to take unorthodox pictures to show it achieves your request.
Table of Contents correctly ordered:
Bottom of TOC page with letter following:
Bottom of the letter page numbered in correct order:
Bottom of the letter followed by the first section which has been indexed to the section 2.
Best Answer
You have to pass the corresponding option to the
\documentclass. You said yourself you found the entry of the Sensors journal in thejournalnames.texfile:so you can see that the declared option name is
sensors(all lower case), so you have to use: