Creating paragraphs with automatic width

Question

I've got a bunch of paragraphs that I'm manually "tabbing out" using hspace of varying degree. After the varying amount of hspace, I'm trying to make a paragraph that fills the remaining width available on the page. Unfortunately, parbox requires a finite width to be passed to it, which isn't known unless I calculate it manually for each paragraph. Is there an easier way to do this?

\documentclass{article}
\begin{document}
\hspace{2in}
\parbox{\linewidth}{I have a whole bunch of text here and it will extend past the edge of the page even though I'd like it to break before the page ends and act like a normal paragraph.}
\end{document}

UPDATE

I'm getting very close, but when I try to add my manually-numbered paragraphs, the right margin gets messed up again.

Here's an example. If I try to use adjustwidth again, it creates a line break after the section number which I don't want.

\documentclass{article}
\usepackage{changepage}
\begin{document}
\begin{adjustwidth}{2.5cm}{}
\parbox{\linewidth}{This paragraph runs to the proper end of the page. It will have a fair bit of space at the end, unlike the next paragraph which will overshoot it because of the makebox that's put in front of it.}
\makebox[2em]{1.1}\parbox[t]{\linewidth}{I have a whole bunch of text here and it will extend past the edge of the page even though I'd like it to break before the page ends and act like a normal paragraph.}
\end{adjustwidth}
\end{document}

Answer 1

Probably you would want to consider using the changepage package. With it you can locally adjust the margins of text in a page with the use of the environment, adjustwidth.

\begin{adjustwidth}{<leftmargin>}{<rightmargin>}
<content>
\end{adjustwidth}

\documentclass{article}
\usepackage{changepage}
\usepackage{lipsum}
\begin{document}
\lipsum[1-2]
    \begin{adjustwidth}{2.5cm}{} % Here 2.5cm defines the extra tabbing you need. The right margin is left untouched to keep the default right margin.
    \lipsum[1-2]
    \end{adjustwidth}
\lipsum[1-2]
\end{document}

For the second question, you can use a list as David Carlisle suggested. This can be achieved as follows:

\documentclass{article}
\usepackage{changepage}
\usepackage{enumitem}
\begin{document}
\begin{adjustwidth}{2.5cm}{}
This paragraph runs to the proper end of the page. It will have a fair bit of space at the end, unlike the next paragraph which will overshoot it because of the makebox that's put in front of it.
    \begin{enumerate}[label=1.\arabic*,leftmargin=*]
    \item I have a whole bunch of text here and it will extend past the edge of the page even though I'd like it to break before the page ends and act like a normal paragraph.
    \end{enumerate}
\end{adjustwidth}
\end{document}

Now playing with lists to make more robust:

\documentclass{article}
\usepackage{changepage}
\usepackage{enumitem}
\newlist{parin}{enumerate}{2} % depth of 2 can be changed depending on the necessity
\setlist[parin,1]{label*=1.\arabic*.,leftmargin=*}
\setlist[parin,2]{label*=\arabic*.,leftmargin=*}
\begin{document}
\begin{adjustwidth}{2.5cm}{}
This paragraph runs to the proper end of the page. It will have a fair bit of space at the end, unlike the next paragraph which will overshoot it because of the makebox that's put in front of it.
    \begin{parin}
    \item I have a whole bunch of text here and it will extend past the edge of the page even though I'd like it to break before the page ends and act like a normal paragraph.
            \begin{parin}
                \item I have a whole bunch of text here and it will extend past the edge of the page even though I'd like it to break before the page ends and act like a normal paragraph.
                \item I have a whole bunch of text here and it will extend past the edge of the page even though I'd like it to break before the page ends and act like a normal paragraph.
            \end{parin}
        \item I have a whole bunch of text here and it will extend past the edge of the page even though I'd like it to break before the page ends and act like a normal paragraph.
            \begin{parin}
                \item I have a whole bunch of text here and it will extend past the edge of the page even though I'd like it to break before the page ends and act like a normal paragraph.
                \item I have a whole bunch of text here and it will extend past the edge of the page even though I'd like it to break before the page ends and act like a normal paragraph.
            \end{parin}
    \end{parin}
\end{adjustwidth}
\end{document}

Answer 2

The way to control margins in LaTeX is to use a list environment (compare the definition of quote in article class).

\documentclass{article}
\begin{document}

\begin{list}{}{\setlength\leftmargin{2in}}\item\relax
I have a whole bunch of text here and it will extend past the edge of the page even though I'd like it to break before the page ends and act like a normal paragraph.
\end{list}
\end{document}