Threeparttable over two columns in landscape

Question

I have a long table with several panels. I want to spread it over two columns in a landscape format. I am using \threeparttable to include table notes. I have tried to get this done both with \minipage and with \tabularx, but I run into several problems: 1. The two columns are not aligned. Since the second part of the table is shorter, it ends up being placed in the middle of the column instead of the top. 2. The table notes are only under the first column. I want them over the length of the entire table. I have tried to insert a third mini page or tabular, but this didn't work. 3. I also want to make sure the caption goes over the entire length of the tables. 4. The scaling is somewhat off. I want the table to fill more of the page, but with the table notes still visible. I am using \adjustbox to fit the table. Here is a MWS:

  \documentclass[11pt,oneside]{amsart}
   \usepackage{lscape}
   \usepackage{multirow}
   \usepackage{adjustbox}
   \usepackage[flushleft]{threeparttable}
   \usepackage[english]{babel} % English
   \usepackage[T1]{fontenc}
   \usepackage{layout}
   \usepackage{setspace}
   \usepackage{booktabs}
  \usepackage{siunitx}

\begin{document}

\begin{landscape}
\begin{table}
\begin{adjustbox}{width=1\textwidth}
\begin{threeparttable}
\caption{Table}
\begin{minipage}{0.5\linewidth}
\begin{tabular}{lcccccc}
\toprule
  \multicolumn{7}{l}{PanelA}
  \midrule
    & Mean & SD & Median & Min & Max & N \\
   Variable A & 1 & 2 & 3 & 4 & 5 & 6 \\
   Variable B & 1 & 2 & 3 & 4 & 5 & 6 \\
   \midrule 
    \multicolumn{7}{l}{PanelB}
   \midrule
       & Mean & SD & Median & Min & Max & N \\
      Variable A & 1 & 2 & 3 & 4 & 5 & 6 \\
      Variable B & 1 & 2 & 3 & 4 & 5 & 6 \\
   \midrule 
 \end{tabular}
\end{minipage}%
 \hspace{2mm}
  \begin{minipage}{0.5\linewidth}
\begin{tabular}{lcccccc}
\toprule
  \multicolumn{7}{l}{PanelA}
  \midrule
    & Mean & SD & Median & Min & Max & N \\
   Variable A & 1 & 2 & 3 & 4 & 5 & 6 \\
   Variable B & 1 & 2 & 3 & 4 & 5 & 6 \\
   \midrule 
    \multicolumn{7}{l}{PanelB}
   \midrule
       & Mean & SD & Median & Min & Max & N \\
      Variable A & 1 & 2 & 3 & 4 & 5 & 6 \\
      Variable B & 1 & 2 & 3 & 4 & 5 & 6 \\
   \midrule 
 \end{tabular}
\end{minipage}%
 \begin{tablenotes}
 \item Table notes are here and should go over the entire length of the table.
 \end{tablenotes}
\end{threeparttable}
\end{adjustbox}
\end{table}
\end{landscape}


\end{document}

Thanks a lot!

Answer 1

like this?

based on answer here and adopted to landscape format:

\documentclass[11pt,oneside]{amsart}
\usepackage{pdflscape}
\usepackage{booktabs, multirow}
\usepackage[flushleft]{threeparttable}
\usepackage{afterpage}

\begin{document}

\afterpage{\clearpage}
\begin{landscape}
\begin{threeparttable}
\caption{Table}
\setlength\tabcolsep{0pt}
\begin{tabular*}{\linewidth}{p{0.45\linewidth}
                             @{\extracolsep{\fill}}
                             p{0.45\linewidth}}
\begin{tabular*}{\linewidth}{@{\extracolsep{\fill}}l *{6}{c}}
    \toprule
\multicolumn{7}{l}{PanelA}            \\
    \midrule
            & Mean  & SD & Median & Min & Max & N \\
Variable A  & 1     & 2  & 3      & 4   & 5   & 6 \\
Variable B  & 1     & 2  & 3      & 4   & 5   & 6 \\
    \midrule
\multicolumn{7}{l}{PanelB}          \\
    \midrule
            & Mean  & SD & Median & Min & Max & N \\
Variable A  & 1     & 2  & 3      & 4   & 5   & 6 \\
Variable B  & 1     & 2  & 3      & 4   & 5   & 6 \\
    \midrule
\end{tabular*}
&
\begin{tabular*}{\linewidth}{@{\extracolsep{\fill}}l *{6}{c}}
    \toprule
\multicolumn{7}{l}{PanelA}            \\
    \midrule
            & Mean  & SD & Median & Min & Max & N \\
Variable A  & 1     & 2  & 3      & 4   & 5   & 6 \\
Variable B  & 1     & 2  & 3      & 4   & 5   & 6 \\
    \midrule
\multicolumn{7}{l}{PanelB}          \\
    \midrule
            & Mean  & SD & Median & Min & Max & N \\
Variable A  & 1     & 2  & 3      & 4   & 5   & 6 \\
Variable B  & 1     & 2  & 3      & 4   & 5   & 6 \\
    \midrule
\end{tabular*}
\end{tabular*}%
\begin{tablenotes}
\item Table notes are here and should go over the entire length of the table.
\end{tablenotes}
\end{threeparttable}
\end{landscape}

\end{document}