I've successfully tested that the timeout option used in WWW::Mechanize::new works as expected for me.

  DB<1> use WWW::Mechanize

  DB<2> $mech = WWW::Mechanize->new (timeout=>300)

  DB<3> x $mech->get ('http://192.168.1.77')
Error GETing http://192.168.1.77: Can't connect to 192.168.1.77:80 (co
+nnect: No route to host) at (eval 35)[/usr/share/perl/5.10/perl5db.pl
+:638] line 2
  DB<4> x $mech->timeout
0  300
  DB<5> x $mech->timeout(1)
0  300
  DB<6> x $mech->timeout
0  1
  DB<7> x $mech->get ('http://192.168.1.77')
Error GETing http://192.168.1.77: Can't connect to 192.168.1.77:80 (co
+nnect: timeout) at (eval 40)[/usr/share/perl/5.10/perl5db.pl:638] lin
+e 2
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Note the difference in error message reported.