Reading Options from DateListPlots with legends

Question

Normally I can recover the options used on a DateListPlot easily with Options[]. However if one of the options said a Legend should be attached, it appears all the options are then unreadable.

For example, here are two plots identical apart from p2 has a legend. I can read the options for p1 fine, but Options on p2 returns nothing.

data1 = {{{2006, 10, 1}, 10}, {{2006, 10, 15}, 12}, {{2006, 10, 30}, 15}, {{2006, 11, 20}, 20}};
data2 = {{{2006, 10, 5}, 15}, {{2006, 10, 20}, 8}, {{2006, 11, 10}, 5}, {{2006, 11, 15}, 1}};
p1 = DateListPlot[{data1, data2}, Joined -> True]
p2 = DateListPlot[{data1, data2}, Joined -> True, PlotLegends -> Automatic]

Options[p1, FrameTicks]
Options[p2]

I am keen to be able to read the FrameTicks option to complete a function to create DateListPlots with 2 y-axis. Alexey Popkov kindly solved what I thought was my final problem, only for this one to appear from behind it:

Combine two DateListPlots and retain a time axis

Answer 1

This is because the structure of the graphics object returned by a plot with a legend is different. You need to look at the option of the first part of the returned object and you should be fine, i.e.

data1 = {{{2006, 10, 1}, 10}, {{2006, 10, 15}, 12}, {{2006, 10, 30}, 
    15}, {{2006, 11, 20}, 20}};
data2 = {{{2006, 10, 5}, 15}, {{2006, 10, 20}, 8}, {{2006, 11, 10}, 
    5}, {{2006, 11, 15}, 1}};
p1 = DateListPlot[{data1, data2}, Joined -> True];
p2 = DateListPlot[{data1, data2}, Joined -> True, 
  PlotLegends -> Automatic];

Options[p1, FrameTicks]
Options[p2[[1]]]


{FrameTicks -> {{Automatic, 
    Automatic}, {{{3368736000, "Oct 02"}, {3369945600, 
      "Oct 16"}, {3371155200, "Oct 30"}, {3372364800, 
      "Nov 13"}, {3373574400, "Nov 27"}, {3369340800, 
      ""}, {3370550400, ""}, {3371760000, ""}, {3372969600, 
      ""}}, {{3368736000, ""}, {3369945600, ""}, {3371155200, 
      ""}, {3372364800, ""}, {3373574400, ""}, {3369340800, 
      ""}, {3370550400, ""}, {3371760000, ""}, {3372969600, ""}}}}}

{FrameLabel -> {None, None}, AspectRatio -> 1/GoldenRatio, 
 AxesOrigin -> {3368649600, 0}, Frame -> True, 
 FrameTicks -> {{Automatic, 
    Automatic}, {{{3368736000, "Oct 02"}, {3369945600, 
      "Oct 16"}, {3371155200, "Oct 30"}, {3372364800, 
      "Nov 13"}, {3373574400, "Nov 27"}, {3369340800, 
      ""}, {3370550400, ""}, {3371760000, ""}, {3372969600, 
      ""}}, {{3368736000, ""}, {3369945600, ""}, {3371155200, 
      ""}, {3372364800, ""}, {3373574400, ""}, {3369340800, 
      ""}, {3370550400, ""}, {3371760000, ""}, {3372969600, ""}}}}, 
 GridLines -> {{{3368736000, GrayLevel[0.8]}, {3369945600, 
     GrayLevel[0.8]}, {3371155200, GrayLevel[0.8]}, {3372364800, 
     GrayLevel[0.8]}, {3373574400, GrayLevel[0.8]}}, None}, 
 Method -> {}, PlotRange -> {{3368649600, 3.37297*10^9}, {0, 20.}}, 
 PlotRangeClipping -> True, 
 PlotRangePadding -> {{86400., 86400.}, {0.4, 0.4}}, Ticks -> None}